Systems and methods for scheduling work items

ABSTRACT

Disclosed herein is a computer implemented scheduling method. The method comprises processing project data to determine one or more team-specific scheduling solutions for work items, each team specific scheduling solution for the work item defining a particular team and one or more iterations of that particular team in which the work item can be completed; identifying from the one or more team-specific scheduling solutions an optimal scheduling solution for the work item, the optimal scheduling solution being selected based at least in part on the number of iterations defined by each of the one or more team-specific scheduling solutions; and scheduling the work item according to the optimal scheduling solution identified for the work item.

COPYRIGHT NOTICE

A portion of the disclosure of this patent document contains materialthat is subject to copyright protection. The copyright owner has noobjection to the facsimile reproduction by anyone of the patent documentor the patent disclosure, as it appears in the Patent and TrademarkOffice patent file or records, but otherwise reserves all copyrightrights whatsoever. Copyright © 2014-2015 Atlassian Pty Ltd.

FIELD OF THE DISCLOSURE

The present disclosure generally relates to systems and methods forscheduling work items that form part of a project.

BACKGROUND

The approaches described in this section are approaches that are knownto the inventors and could be pursued. They are not necessarilyapproaches that have been pursued. Therefore, unless otherwiseindicated, it should not be assumed that any of the approaches describedin this section qualify as prior art merely by virtue of their inclusionin this section, or that those approaches are known to a person ofordinary skill in the art.

Various project planning systems and applications exist. Generallyspeaking, a purpose of project planning systems is to determinerealistic delivery dates of individual work items that make up a projectand to coordinate execution/delivery of those work items towards largerprojects.

A large number of constraints can influence the scheduling of work itemsand, ultimately, whether any determined schedule is viable. By way ofexample, constraints can include the available resources (human orotherwise), the capacity of those resources over time, the skills orcapabilities of the resources, interdependencies between work items, andtask/project deadlines.

The various competing constraints make determining an appropriateschedule for work items a complex task.

SUMMARY

The appended claims may serve as a summary of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a timeline showing iterations (e.g. sprints) of differentteams;

FIG. 2 is a flowchart illustrating high level stages involved in aniteration aware work item scheduling process;

FIG. 3 is a timeline illustrating a schedule of work items.

FIG. 4 is a flowchart illustrating preprocessing performed in aniteration aware work item scheduling process;

FIG. 5 is a flowchart illustrating a process for scheduling a selectedwork item;

FIG. 6 is a flowchart illustrating a process for identifying ascheduling solution for a work item in accordance with one embodiment;

FIG. 7 is a flowchart illustrating a process for identifying ascheduling solution for a work item in accordance with an alternativeembodiment;

FIG. 8 is a flowchart illustrating a process for generating a set ofsolution candidates;

FIG. 9 is a flowchart illustrating high level stages involved in arelease (and iteration) aware work item scheduling process;

FIG. 10 is a flowchart illustrating preprocessing performed in a releaseaware work item scheduling process;

FIG. 11 is a flowchart illustrating a process for scheduling strictlyassigned work items into releases;

FIG. 12 is a flowchart illustrating a process for schedulingunconstrained release work items into releases;

FIG. 13 illustrates a client server architecture; and

FIG. 14 illustrates a computer system which may be used to implementvarious embodiments.

DETAILED DESCRIPTION

In the following description, for the purposes of explanation, numerousspecific details are set forth in order to provide a thoroughunderstanding of the present invention. It will be apparent, however,that the present invention may be practiced without these specificdetails. In other instances, well-known structures and devices are shownin block diagram form in order to avoid unnecessary obscuring.

The present disclosure generally relates to systems and computerimplemented methods for automatically planning or scheduling work items,or for assisting in the planning or scheduling of work items. In orderto illustrate various features, project planning in a softwaredevelopment context—and in particular using agile methodologies—wil bedescribed. The features described herein can, however, be used/adaptedto plan (or assist in the planning of) other types of projects andprojects which employ alternative methodologies.

The disclosure is set out in the following sections:

-   -   1. General overview of software development considerations.    -   2. Iteration aware scheduling.        -   2.1. Iteration aware scheduling problem description.        -   2.2. Computer implemented method for iteration aware            scheduling.        -   2.3. Iteration aware scheduling clauses.    -   3. Automatic assignment of work items to team resources.        -   3.1. Computer implemented method for automatically assigning            work items to team resources.        -   3.2. Automatic assignment of work items to team resources            clauses.    -   4. Release aware scheduling.        -   4.1. Release aware scheduling problem description.        -   4.2. Computer implemented method for release aware            scheduling.        -   4.3. Resource aware scheduling clauses.    -   5. System architecture suitable for implementing/providing one        or more of the features described herein.    -   6. Hardware suitable for implementing/providing one or more        features described herein.

1. Overview of Software Development Considerations

Historically, software development was undertaken using a traditionalengineering project approach. This approach involves a sequentialdevelopment process (e.g. the waterfall model) which divides thedevelopment into distinct stages: requirements analysis, design,implementation, testing, integration, deployment, maintenance. In asequential development process the output of one development phase iseffectively the input to the next development phase.

While the waterfall model may still be used for some projects, currentsoftware (and potentially other) development projects often employother, more flexible, development methodologies. Agile development isone such group of methodologies, specific examples of which includescrum, kanban, scrum ban, and other known agile methodologies. Teamsworking within agile methodologies have particular requirements andneeds when it comes to scheduling/planning work that is to be performedacross defined time frames and by multiple teams working in parallel.These needs and requirements differ from those that accompanytraditional project management methodologies.

As one agile example, in a scrum methodology the available humanresources work in teams, and each team works in defined lengthiterations (often referred to as sprints). Ideally, each iteration has adefined set of work associated with it, the goal of a given iterationbeing to complete that set of work and deliver a working and potentiallyshippable product increment. Larger projects are usually delivered insmall increments in order to get early feedback and, if necessary, toallow early adjustment to be undertaken rather than only evaluating atthe very end of a project.

Iteration durations are typically short, for example 1 to 4 weeks,though can be shorter/longer. A common iteration duration is 2 weeks. Agiven team can have iterations of different durations, different teamscan have iterations of different durations compared to one another,and/or the iterations of the teams may start at different times. This isillustrated in FIG. 1. In the time period represented by FIG. 1, team Ais shown to have three iterations 102A-102C which each have the sameduration. Team B has two iterations 102D-102E, each of which are thesame duration, but a different duration to the iterations of team A. Dueto this different duration, the start time of team B's iteration 102Edoes not align with the start time of any of team A iterations (fallingin the middle of team A iteration 102B). Team C has two completeiterations 102F and 102G which have different durations.

The iterations of the teams cause problems with existing schedulingsystems and methodologies. By way of illustration, consider a work item104 that is assigned to team A. Work item 106 is dependent on work item104 (i.e. work item 106 cannot be commenced until work item 104 iscomplete) and due to skill/capability requirements must be completed byteam B or Team C. Based on these requirements, work item 106 has anearliest start date of T1 (i.e. the end of team A iteration 1 andanticipated completion date of work item 104). Under existing schedulingsystems work item 106 would be scheduled to commence as early aspossible—at T1. By assigning work item 106 to team B to start at T1 (see106A) or to team C to start at T1 (see 106B), however, the work itemwould not start at the beginning of an iteration and will span acrossmultiple iterations. These consequences are not, generally speaking,desirable. Instead, the work item should be scheduled to start at thestart of Team B or Team C's next iteration (T2 or T3). This is despitethe fact that T2 and T3 are some days after the earliest possible startof task 106.

In order to account for teams working in iterations (or sprints) whenscheduling tasks iteration aware scheduling processes are described insections 2 and 3 below. The iteration aware scheduling processesgenerate and make use of an additional time abstraction layer. Inaddition to a global time axis on which tasks are scheduled, each teamis provided with its own additional time axis which is defined by theiterations that team works in (the iterations being non-overlapping timesegments). This time axis imposes additional constraints that areconsidered when scheduling tasks. In addition to allowing the schedulingof work items to be performed within the context of iterations, the timeaxis/constraints applied have the effect of reducing the solution spaceof the work item scheduling problem. Rather than generating a scheduleon a daily basis teams are scheduled for each iteration.

Further, by taking into account iterations when attempting to schedulework items priority is placed on minimizing the number of iterationsthat are required in order to complete the work item. This can becontrasted with other task scheduling processes where the end date of aschedule is prioritized.

Section 4 goes on to describe an embodiment in which the iteration awarescheduling processes are extended to take into account releases—i.e.project milestones or other deliverables.

Agile methodologies also enable complexity-based estimation techniques(e.g. story-point based estimation) to be used when planning/schedulingwork items. This involves estimating using a relative unit of complexity(e.g. story points). Correspondingly, teams measure/estimate how manycomplexity units can be achieved by the team members in a giveniteration (commonly referred to as the team's velocity). Ascomplexity-based estimates don't have a direct relation to time, workitems cannot be scheduled on a time basis within an iteration. Rather,the whole iteration needs to be taken as the unit of planninggranularity.

2. Iteration Aware Scheduling

This section describes a scheduling process which takes into accountiterations (or sprints) in which teams work when scheduling work items.

2.1 Iteration Aware Scheduling Problem Description

This section provides an overview of various concepts that are relevantto the problem of scheduling work items that make up a project (ormultiple projects) across teams available to work on those work itemswhilst at the same time taking into account iterations in which thoseteams work.

Workflow and Stages

In agile methodologies the basic work item is the user story. A workitem/user story is denoted as p, and the set of all work items that needto be scheduled is denoted

(pϵ

).

In one implementation a work item p can pass through a defined workflow. In this case a work flow is set up for the entire schedule (orroadmap) and consists of a sequence of stages q. The set of all stagesof a work flow is denoted Q (qϵQ).

Skills s can be defined and, where used, are associated with workitems/stages as well as resources. Skills associated a stage indicatethe skills required to complete that stage and skills held by/associatedwith a resource indicate the skills that resource is able to contributeto a stage. In one implementation the set of all skills is denoted S(sϵS). Each stage q is associated with a set of one or more skills srequired to complete that stage. The set of skills relevant to aparticular stage is denoted S_(q) (S_(q) ⊂S). The set of skills for agiven stage are mutually disjoint such that the stage of a given skillq_(s) is strictly defined.

The time in which work items can be scheduled by the scheduling method(i.e. how far ahead scheduling method plans) is denoted by the interval[0, {tilde over (T)}], ({tilde over (T)}ϵ

). {tilde over (T)} will be referred to as the planning horizon. Eachtime step in [0, {tilde over (T)}] represents a planning interval, forexample 1 day. Alternative planning intervals could be adopted asappropriate, for example a set number of minutes/hours/day/weeks etc.

Resources and Teams

A resource that is available to work on a work item is denoted r. Aresource may be a human resource (e.g. an employee) or a non-humanresource (e.g. a piece of equipment, a room etc.). The set of allavailable resources is denoted

(rϵ

).

For every resource r and skill s a value η_(rs) (η_(rs)ϵ{0,1}) isprovided which indicates whether the resource r is proficient in theskill s. With this in mind the skill set of a resource is defined asS_(r) (S_(r)=(s|η_(rs)>0)) and the stage set of a resource is defined asQ_(r) (Q_(r)={q|S_(q)∩S_(r)≠∅}).

An iteration availability is also provided for every resource: R_(rt)(R_(rt)ϵ

₀ ⁺). The iteration availability for a resource is a sum of the dailyavailabilities of that resource in the iteration. Iteration availabilitycan be computed based on a resource's normal weekly working hours andabsences (e.g. holidays) during the iteration in question.

Resources are organized into teams. A team is denoted q and the completeset of teams is denoted

(gϵ

). For the purposes of the scheduling method a resource is assigned toexactly one team. Accordingly, and by way of example, if a singleemployee works 20 hours a week time in team A and 20 hours a week inteam B the scheduling method will treat this as two separate resources(one a member of team A with 20 hours of availability per week, and onea member of team B with 20 hours of availability per week). The team towhich a resource is assigned is denoted g_(r). The set of resources of ateam is denoted

_(g). The set of skills available in a team is denoted S_(g) (S_(g)being the union of all skills held by all resources assigned to theteam).

As noted, in agile methodologies teams partition their time in asequence of work slots or iterations. An iteration is denoted t, and theset of all a team's iterations is denoted

_(g) (tϵ

_(g)). Each iteration is characterized by a start time ST_(t) and an endtime ET_(t). For a given iteration t, ST_(t)<ET_(t) and ST_(t) andET_(t) each fall within (or on the bounds of) the interval [0, {tildeover (T)}]. A given iteration t starts after the preceding iterationends. Iterations t can be individually defined by a user and/orgenerated by the system based on defined parameters such as a startingtime/date and the normal duration of the team's iterations.

For convenience, the iterations assigned to a given resource (

_(T)) are the same as the iterations defined for the team that resourceis a member of (

_(g)). The time-step availability of resources

_(rt) is defined for every iteration as the sum of time-stepavailabilities in the iteration interval and is therefore also anelement of

₀ ⁺.

Work Demand

As noted, the basic work item p in agile methodologies is the userstory. The work package of a user story is defined by a number of skilldemands denoted by

_(ps) (

_(ps)ϵ

⁺). Based on this demand values of the sequence of stages (Q_(p)) of awork item p is defined as the roadmap stage sequence which does notinclude the stages with no demand for the work item. This can bedetermined because each skill is assigned to exactly one stage.

Furthermore the work items are ranked in the backlog of work items. Thisranking is absolute in the sense that each work item has a higherpriority than all its successors together. The ranking of a work item inthe backlog defines the value of the work item. Phrased alternatively,the higher priority a work item has the higher its value.

Dependencies between work items are also taken into account. These aremodelled as a directed acyclic graph G^(<)=(

,

). The set of predecessors

_(p) ^(<) of a given work item must be worked off before the given workitem can be started.

The earliest start time for a work item can also be defined, and isdenoted EST_(p) (EST_(p)ϵ[0,{tilde over (T)}]).

A further constraint is the limitation of the maximum number ofresources permitted to work on a given stage of a work item. This iscontrolled by the parameter L (Lϵ

), which is used as a limitation.

A further constraint is that a given work item (story) must beimplemented by exactly one team.

Iteration Aware Scheduling Problem Description

A mixed integer linear program is provided to solve the problem ofscheduling a set of work items

with the constraints described above. This section provides aformalization of the problem.

For this formalization a given work item/user story p is decomposed intoactivities denoted a, the set of all activities being denoted

(aϵ

). Each activity a represents a stage of the original work item p. Anactivity a has associated work demands

_(as) (

_(as)ϵ

⁺) that correspond to the values of the stage represented by thatactivity.

A directed acyclic graph of the set of activities is used: G^(A<)=(A,ϵ). The set of arcs/edges ϵ model the linear dependencies of the stagesand the prerequisite relations between different work items.

Work Constraints

Initially the set of continuous variables that quantify the amount ofwork to be done for a given activity by a given resource in one of itsiterations using one of its skills is defined. This is shown indefinition 1 below. The constraint shown in definition 2 makes sure thatresources are not overbooked

$\begin{matrix}{{x_{arts} \in {\mathbb{R}}_{0}^{+}}{{a \in \mathcal{A}},{r \in \mathcal{R}},{t \in \mathcal{T}_{r}},{s \in \mathcal{S}_{ar}}}} & {{Definition}\mspace{14mu} 1} \\{{{\sum\limits_{a \in \mathcal{A}}\;{\sum\limits_{s \in \mathcal{S}_{ar}}\; x_{arts}}} \leq \mathcal{R}_{rt}}{{r \in \mathcal{R}},{t \in \mathcal{T}_{r}}}} & {{Definition}\mspace{14mu} 2}\end{matrix}$

Work Demand

Work demand is implemented by introducing a set of binary decisionvariables denoting whether or not a work a work item is scheduled(definition 3 below) and, if the work item is scheduled, enforcing thatscheduled activities meet their work requirements (definition 4 below).

$\begin{matrix}{{y_{p} \in \left\{ {0,1} \right\}}{p \in \mathcal{P}}} & {{Definition}\mspace{14mu} 3} \\{{{\sum\limits_{r \in \mathcal{R}}\;{\sum\limits_{t \in \mathcal{T}_{r}}\; x_{arts}}} = {y_{p}*\mathcal{D}_{as}}}{{a \in \mathcal{A}_{p}},{s \in \mathcal{S}_{a}}}} & {{Definition}\mspace{14mu} 4}\end{matrix}$

Resource Assignment

In order to implement the limitation on assigned resources per activity,binary variables are introduced to indicate the fact that a resource isworking on an activity (definition 5 below). The constraint shown indefinition 6 below couples these variables with the continuous decisionvariables. The constraint shown in definition 7 then limits the numberof assignments based on the maximum resource constraint parameter L(which defines the number of resources that can work on the work item).

$\begin{matrix}{{y_{ar} \in \left\{ {0,1} \right\}}{{a \in \mathcal{A}},{r \in \mathcal{R}}}} & {{Definition}\mspace{14mu} 5} \\{{{y_{ar}*M} \geq {\sum\limits_{t \in \mathcal{T}_{r}}\;{\sum\limits_{s \in \mathcal{S}_{r}}\; x_{arts}}}}{{a \in \mathcal{A}},{r \in \mathcal{R}}}{M\mspace{14mu}{is}\mspace{14mu} a\mspace{14mu}{sufficiently}\mspace{14mu}{large}\mspace{14mu}{constant}\mspace{14mu}{\left( {{e.g.\mspace{14mu} 10}\mspace{20mu}{million}} \right).}}} & {{Definition}\mspace{14mu} 6} \\{{{\sum\limits_{r \in \mathcal{R}}\; y_{ar}} \leq L_{a}}{a \in \mathcal{A}}} & {{Definition}\mspace{14mu} 7}\end{matrix}$

Team Assignment

A single team assignment is enforced by introducing binary variables forevery team (definition 8 below). The constraint shown in definition 9below couples these variables with the continuous decision variables,and the actual limitation is added in the constraint shown in definition10.

$\begin{matrix}{{y_{pg} \in \left\{ {0,1} \right\}}{{p \in \mathcal{P}},{g \in \mathcal{G}}}} & {{Definition}\mspace{14mu} 8} \\{{{y_{pg}*M} \geq {\sum\limits_{a \in \mathcal{A}}\;{\sum\limits_{r \in \mathcal{R}_{g}}\;{\sum\limits_{t \in \mathcal{T}_{r}}\;{\sum\limits_{s \in \mathcal{S}_{ar}}\; x_{arts}}}}}}{{p \in \mathcal{P}},{g \in \mathcal{G}}}} & {{Definition}\mspace{14mu} 9} \\{{{\sum\limits_{g \in \mathcal{G}}\; y_{pg}} \leq 1}{p \in \mathcal{P}}} & {{Definition}\mspace{14mu} 10}\end{matrix}$

Dependencies

To ensure correct handling of the dependency constraint betweenactivities a further set of binary decision variables is defined toindicate that an activity is being executed in a given iteration(definition 11 below). The coupling constraints are given in definition12. Further, integer variables are introduced to model the start time ofan activity st_(α) (definitions 13 and 14 below) and the end time of anactivity et_(α) (definitions 15 and 16 below). A constraint is alsointroduced to ensure that the start time of an activity is greater(later) than the end time of its predecessors (definition 17).

$\begin{matrix}{{y_{at} \in \left\{ {0,1} \right\}}{{a \in \mathcal{A}},{t \in \mathcal{T}}}} & {{Definition}\mspace{14mu} 11} \\{{{y_{at}*M} \geq {\sum\limits_{r \in \mathcal{R}}{\sum\limits_{s \in \mathcal{S}_{ar}}x_{arts}}}}{{a \in \mathcal{A}},{t \in \mathcal{T}}}} & {{Definition}\mspace{14mu} 12} \\{{{st}_{a} \in \left\lbrack {0,\overset{\_}{T}} \right\rbrack}{a \in \mathcal{A}}} & {{Definition}\mspace{14mu} 13} \\{{{st}_{a} \leq {y_{at}*{ST}_{t}}}{{a \in \mathcal{A}},{t \in \mathcal{T}}}} & {{Definition}\mspace{14mu} 14} \\{{{et}_{a} \in \left\lbrack {0,\overset{\_}{T}} \right\rbrack}{a \in \mathcal{A}}} & {{Definition}\mspace{14mu} 15} \\{{{et}_{a} \leq {y_{at}*{ET}_{t}}}{{a \in \mathcal{A}},{t \in \mathcal{T}}}} & {{Definition}\mspace{14mu} 16} \\{{{{et}_{a_{1}} + 1} \leq {{st}_{a_{2}}\left( {a_{1},a_{2}} \right)}} \in ɛ} & {{Definition}\mspace{14mu} 17}\end{matrix}$

Earliest Start

To implement the earliest start time (EST) constraint the activity startvariable already defined for the dependency constraints is used(definition 18 below).st_(α)≥EST_(α) αϵ

  Definition 18

Iteration Aware Scheduling Optimization

A hierarchy of objective functions (in decreasing importance) isdefined:

-   -   1) Work flow    -   2) Work item (story) value    -   3) Weighted completion times

Work Flow

The topmost priority is to ensure a structured work flow by minimizingthe number of iteration violations.

An iteration violation occurs where an additional iteration needs to beused to complete a work item. For example, a work item that can becompleted in a single iteration does not have any iteration violations.A work item that requires two iterations has a single iterationviolation. A work item that requires three iterations has two iterationviolations and so forth.

This priority is provided in definition 19:

$\begin{matrix}{\min{\sum\limits_{a \in \mathcal{A}}\;{\sum\limits_{t \in \mathcal{T}}\; y_{at}}}} & {{Definition}\mspace{14mu} 19}\end{matrix}$

Work Item (Story) Value

The first objective independent of the presence of strictly scheduledwork items (i.e. work items that are strictly assigned to a particularrelease, as described in further detail below) is to maximize theaggregated value of scheduled work items. Given weight values for workitems W_(p), the objective provided in definition 20 is given:

$\begin{matrix}{\max{\sum\limits_{p \in \mathcal{P}}\;{y_{p}*\mathcal{W}_{p}}}} & {{Definition}\mspace{14mu} 20}\end{matrix}$

Weighted Completion Times

Solutions where more important work items are completed before lessimportant/minor work items are preferred. Accordingly, the weightedcompletion time is minimized (see definitions 21, 22, and 23 below):

$\begin{matrix}{\min{\sum\limits_{p \in \mathcal{P}}\;{{et}_{p}*\mathcal{W}_{p}}}} & {{Definition}\mspace{14mu} 21} \\{{{et}_{p} \geq {et}_{a}}{{p \in \mathcal{P}},{a \in \mathcal{A}_{p}}}} & {{Definition}\mspace{14mu} 22} \\{{{et}_{p} \in \left\lbrack {0,\overset{\_}{T}} \right\rbrack}{p \in \mathcal{P}}} & {{Definition}\mspace{14mu} 23}\end{matrix}$

2.2 Iteration Aware Scheduling Method

The optimization problem described above is a mixed integer linearproblem (MILP). This may be input into a general purpose solver (e.g.CPLEX) to find the optimal solution.

One issue with this general approach is the potential size of theproblem. Users may generate plans with thousands of work items andhundreds of resources spanning over horizons of several years. At thetime or this application problems of this size are not practicallysolvable in any reasonable time frame.

Furthermore, the problem is inherently stochastic. The estimation ofcomplex tasks (as often arise in software engineering) is alwaysdifficult. The resources that are being allocated are typically humanresources which means that actual availability and performance are notas deterministic as is proposed by the model.

These factors limit the value of an optimal solution significantly.

Approximate solutions can, however, be acceptable to users and becalculated in significantly shorter time frames. Accordingly, in thepresent embodiment a heuristic implementation is used which is based onsearch methods/algorithms and problem decomposition. This decreases thetime complexity as well as the required computing power/resources.

This section provides a detailed example of a computer implementedmethod for automatically scheduling project tasks whist taking theiterations in which teams work into account. The method is implementedby a computer processing system, one example of which is described insection 6 below.

As described above data relevant to the task scheduling method includeinformation regarding resources, teams, skills, and work items. Thisdata will be generally referred to as project data. Some project data isdefined by users and some project data is calculated/generated by thework item scheduling process discussed below. Project data may be inputand/or stored in a various ways. In the present embodiment tables areused.

Table 1 below is an example of a table used to capture/store datarelating to resources. In this example each resource record can include:a team identifier identifying the team to which the resource belongs; aresource identifier for identifying the resource (team member) to whichthe row/record relates: the availability of the resource; plannedabsences for the resource; weekly hours that the resource spends in theindicated team; the skill(s) of the resource: and the iteration scheduleof the team to which the resource belongs.

TABLE 1 Resources Weekly Hours Team Resource Available Absent in TeamSkills Team Schedule A Member A Always None 40 1 Scrum (2 weeks) AMember B Always None 20 1, 2 B Member C Always None 32 3 Scrum (3 weeks)B Member D Always None 40 1, 2, 3 B Member B Always None 20 1, 2 CMember D Always None 40 1, 2, 3 Scrum (2 C Member E Always None 40 3weeks), sprints starting on Tuesdays. Extended sprint 2 from 16 Jan.2015 to 11 Feb. 2015

As can be seen in Table 1, resource B spends 20 hours a week in team Aand 20 hours a week in team B. In this case, when calculating taskassignments resource B will effectively be considered as two separateresources: one resource being dedicated to team A for 20 hours a week,and one resource being dedicated to team B for 20 hours a week.

Table 2 below is an example of a table used to capture/store datarelating to work items. In this example each work item record caninclude: a work item identifier, identifying the work item; a teamidentifier which, once calculated, indicates the team to which the workitem is assigned; an earliest start date/time which indicates theearliest start date/time for the work item; a depends on field recordingwork item interdependencies; a scheduled start date/time which (once theschedule has been calculated) indicates when the work item is scheduledto start; a scheduled end date/time which (once the schedule has beencalculated) indicates when the work item is scheduled to end; a timeestimate (est) indicating the number of time units (e.g. hours) the workitem will consume; a required skills field indicating the skillsrequired to complete the work item; a priority rank field indicating thepriority of a work item; a project identifier indicating the projectwhich the work item is part of.

TABLE 2 Work items Work Earliest Depends Sched Sched Est Skill SkillSkill item Team Start on start end (h) 1 2 3 Priority Project A (Calc)(Calc) (Calc) 290 95 45 150 A A.1 (Calc) (Calc) (Calc) 290 95 45 150 AA.1.1 Team B (Calc) (Calc) 100 100 1 A A.1.2 Team C (Calc) (Calc) 40 2020 2 A A.1.3 (Calc) A1.1 (Calc) (Calc) 50 50 3 A A.1.4 (Calc) 15 Jan.2015 (Calc) (Calc) 100 25 25  50 4 A

Tables such as 1 and 2 above may be presented to a user via anappropriate user interface so that the user can enter relevant data inrespect of the project. In some cases, the tables may be entirely orpartially pre-populated from already available information. The user canthen enter information into the fields provided, the information beingstored for use in the task scheduling process. The values that a userdoes not specify are automatically filled once the scheduling processhas been performed and the relevant values have been calculated.

Data may be captured/stored/presented in alternative ways.

FIG. 2 provides a flowchart 200 which depicts the high level stagesinvolved scheduling tasks taking into account iterations in which teamswork. Each of the high level stages represented by flowchart 200 will bedescribed in detail following the general description.

At 202 preprocessing is performed to identify and remove work items thatcannot be completed and resources that cannot contribute to the taskscheduling process.

At 204 the next work item to be scheduled is identified.

At 206, an attempt to schedule the work item selected at 204 is made.

At 208 a check is made to determine whether further work items requirescheduling. If so the process returns to 204. If not the scheduling iscomplete.

Once the scheduling process is complete the schedule calculated ispresented to a user. By way of example, the tables described above maybe used to present scheduling information to a user by populating thefields calculated by the scheduling method (e.g. populating the Team,members, scheduled start, and scheduled end fields in the work itemstable). Continuing with the example provided in Tables 1 and 2 above,Table 3 shows the updated work item table following the schedulingprocess:

TABLE 3 Work items following scheduling process Work Earliest DependsSched Sched Est Skill Skill Skill item Team Start on start end (h) 1 2 3Priority Project A A, B, C  1 Jan. 2015 11 Feb. 2015 290 95 45 150 A A.1A, B, C  1 Jan. 2015 11 Feb. 2015 290 95 45 150 A A.1.1 Team B  1 Jan.2015 21 Jan. 2015 100 100 1 A A.1.2 Team C  6 Jan. 2015 15 Jan. 2015 4020 20 2 A A.1.3 A A1.1 29 Jan. 2015 11 Feb. 2015 50 50 3 A A.1.4 B 15Jan. 2015 22 Jan. 2015 11 Feb. 2015 100 25 25  50 4 A

A visual timeline may also be generated and presented to a user toillustrate the resulting scheduling. FIG. 3 provides an example of sucha timeline 300 depicting the scheduling of work items A.1.1, A.1.2,A.1.3, and A.1.4 of the example above. As can be seen: work item A.1.1has been scheduled into iteration 1 of Team B; work item A.1.2 has beenscheduled into iteration 1 of Team C; work item A.1.3 has been scheduledinto iteration 3 of Team A; and work item A.1.4 has been scheduled intoiteration 2 of Team B.

Calculated schedule information may also (or alternatively) becommunicated to other processes or applications which may use thescheduling information for downstream purposes.

Preprocessing: 202

Preprocessing is performed at 202 in order to prune or simplify thesearch space of the optimization problem. This assists in reducing thesize of the problem space and, accordingly, the processing time andmemory usage required to perform task scheduling. Generally speakingthis involves removing work items that cannot be scheduled and resourcesthat cannot contribute to the work items from further processing.

FIG. 4 provides a flowchart 202 illustrating preprocessing performed inin accordance with one embodiment.

At 402, work items which have circular/cyclic dependencies and, as such,cannot be executed, are identified and removed from further processing.Circular dependencies can be identified by processing the set of workitems (including the dependencies between work items) using known cycledetection or topological sorting algorithms.

At 404, work items that require any skill that is not held by any of theavailable resources are identified and removed from further processing.If a given work item requires a skill that is not held by any resourcethe work item cannot be completed. In this case the work item removedfrom the set of work items. Conversely, if all skills required for agiven work are available the work item can potentially be completed andit is not removed from the set of work items.

At 406, work items that have invalid dependencies are identified andremoved from further processing. At 406 a work item will have an invaliddependency if it is dependent on a work item that has been removed fromthe set of work items: i.e. if it is dependent on a work item identifiedat 402 to be circularly dependent or if it is dependent on a work itemidentified at 404 to require an unavailable skill.

The removal of cyclic dependencies (and work items dependent thereon)ensures that the dependency graph G is an acyclic dependency graph.

Where work items are removed at 402, 404 or 406 an alert is raised to auser via a user interface. In this case the alert may indicate any workitems that have been removed together with the reason for their removal:e.g. cyclically dependent, unavailable skills (together with thespecific skills that are required and are not available), or dependenton such a work item.

At 408 resources that do not have availability to assist are identifiedand removed from further processing. This involves checking theavailability of each resource R_(rt) against the planning horizon {tildeover (T)}. If a resource r does not have any availability before theplanning horizon it is determined to be unavailable and removed from theset of resources

. If the resource does have availability before the planning horizon itis not removed from the set of resources (at least at this stage).

At 410 resources that do not hold any skills required by any of the workitems are identified and removed from further processing. This involvesprocessing each resource r by checking the skil set of the resourceS_(r) against the superset of all skills required by all work items p inthe set of work items

. If the skill set for a given resource and the superset of skillsrequired for all work items are disjoint, the resource is not needed forany work item and is removed from the set of resources. Conversely, ifthe skill set of a given resource and the superset of work item skillsoverlap/intersect the resource can contribute and is not removed fromthe set of resources.

Determination of Next Work Item to be Processed: 204

In the scheduling process the work items p in the set of work items

are scheduled in turn. The next work item p to be scheduled isdetermined at 204.

In one embodiment the order in which the work items are scheduled isdetermined by processing the backlog of work items (i.e. the work itemsin the set of work items that have not yet been scheduled) to identifythe first or highest priority (defined and stored, for example, in awork item table) work item without an unscheduled predecessor. As thepreprocessing described above removes any circular dependencies the workitems form one or more directed acyclic graphs and an eligible work itemwill be available.

In light of this, a variety of techniques can be used to determine theorder in which work items are processed, for examplelinearization/topological sorting algorithms.

Work Item Scheduling: 206

Once a work item p has been identified an attempt is made to schedulethat work item at 206. The work item being scheduled will be referred toas the current work item.

Generally speaking, scheduling the current work item involves trying tofind a scheduling solution that:

-   -   1) minimizes the number of iteration violations; or    -   2) where multiple solutions yield the same minimum number of        iteration violations, minimizes the number of iteration        violations and provides an earliest end time.

This involves attempting to find a scheduling solution that falls withina defined time interval.

FIG. 5 provides a flowchart 206 illustrating the process of scheduling awork item identified in 204 in accordance with one embodiment.

At 502 the lower and upper time bounds for the defined time interval areinitially determined.

The lower time bound does not change over the course of process 206,however the upper time bound can change as more optimal schedulingsolutions (i.e. scheduling solutions that result in the current taskhaving an earlier end time) are identified.

The lower bound of the time interval is determined to be the latest of:

-   -   the start time of the first iteration (of any team that can be        assigned to the work item) that is at or after the earliest        possible start for the current work item; and    -   the start time of the first iteration (of any team) that is        after the end time of any preceding work items which the work        item in question is dependent on.

The earliest possible start time for the current work item is determinedaccording to the latest end time of any work item(s) the current workitem is dependent on. The end times of work items are determined as thescheduling process progresses and work items are scheduled.

In the present process the upper bound of the time interval is initiallydetermined to be the planning horizon {tilde over (T)}. In the releaseaware scheduling process described in section 4 below a different upperbound of the time interval may be used.

Over the course of process 206 each team g in the set of teams

is in turn considered with respect to the current work item p. If thecurrent team being considered yields the best scheduling solution forthe current work item so far, that scheduling solution is adopted as thecurrent optimal solution. Otherwise the scheduling solution for thecurrent team is discarded and the next team is considered (providedthere are further teams).

At 504 a current team to be considered to schedule the current work itemis selected. The teams may be considered in any deterministic order.

At 506 an attempt is made to identify a team-specific schedulingsolution for the current work item. A team-specific scheduling solutionis a solution in which the work item (selected at 204) is assigned toone or more specific resources of the current team (selected at 504) tobe completed. The team-specific scheduling solution need not necessarilyinvolve all resources of the specific team. Two methods for identifyinga team-specific scheduling solution for a given work item are describedin detail below: one with reference to FIG. 6 and the other in withreference to FIG. 7 and FIG. 8.

If a team-specific scheduling solution for the current team isidentified at 506, a set of assignments (e.g. tuples) is returned. Eachassignment defines an activity of the work item, a resource (assigned towork on the activity), an iteration (in which the resource works on theactivity), a resource commitment (e.g. a number of story points, hours,or other measure that the resource will spend on the activity in theiteration), and one or more skill(s) (used by the resource to work onthe activity). An assignment also defines (or is associated with) anumber of iteration violations (0 or more). If no team-specificscheduling solution for the current work item/current team is identifieda message is returned advising of this.

At 508 the output of the current work item scheduling attempt performedat 506 is checked. If scheduling the current work item using the currentteam was not possible the process proceeds to 510.

If, at 506, a team-specific scheduling solution for the current workitem/current team was identified, a check is performed at 512 todetermine whether the solution is the best or optimal solution so far.If there is no current optimal solution the solution identified at 506is the optimal scheduling solution. If there is a current optimalsolution this is compared against the solution returned by 506 using thefollowing optimization:

-   -   1) The solution returned at 506 is preferable to the current        optimal solution if it has fewer iteration violations.    -   2) If the number of iteration violations of the solution        returned at 506 is equal to the number of iteration violations        of the current optimal solution the solution returned at 506        will be preferable if the solution returned at 506 has an        earlier end date.

If the solution returned at 506 and the current optimal solution havethe same number of iteration violations and the same end date thesolutions are equivalent from an optimization perspective. In this caseeither solution can be adopted (e.g. the solution most recently returnedat 506 may be treated as not being the optimal solution).

If the solution returned at 506 isn't better than the current optimalsolution the process proceeds to 510 to see whether additional teamsneed to be processed.

If the solution returned at 506 is better than the current optimalsolution (or there is no existing optimal solution) the returnedsolution is recorded as the current optimal solution at 514. Inaddition, if the solution returned at 506 has an earlier end date thanthe current optimal solution the upper time bound is updated to reflectthe earlier end date provided by the solution returned at 506. Theprocess then proceeds to 510 to see whether additional teams need to bechecked.

At 510 a check is performed to determine whether one or more teams existfor which an attempt to identify a potential scheduling solution has notyet been made. Once an attempt has been made to identify a team-specificscheduling solution for a given team that team is not reconsidered forthe current work item. If additional teams do exist, the process returnsto 504 to select the next team and to try and identify (at 506) ascheduling solution for that team.

If, at 510, no further teams exist a check is performed at 516 todetermine if a scheduling solution exists for the current work item(e.g. whether there is a currently recorded optimal solution). If so theoptimal scheduling solution is returned and the work item is scheduledaccording to that solution.

If, at 516, no scheduling solution exists an error is returned at 518.In this case it was not possible to automatically schedule the workitem. If the work item cannot be scheduled the error is raised, forexample, by displaying a message on a user interface advising a userthat the work item cannot be scheduled. If a work item cannot bescheduled any downstream work items that are dependent on theunschedulable work item will also be unschedulable. The error messagemay also advise the user of such downstream dependent work items.Unschedulable work items (and work items dependent on such work items)are removed from the backlog of work items.

Identifying a Team-Specific Scheduling Solution for a Given Work Itemand a Given Team: 506

During the work item scheduling process (at 506) each team g in the setof teams

is iterated through to try and identify a team-specific schedulingsolution for that team (or, specifically, for one or more resources ofthat team) for the given work item p.

Generally speaking this process aims to identify a scheduling solutionfor the given work item that (primarily) minimizes the number ofiteration violations and (secondarily) has the earliest end time for thework item. One process for identifying a team-specific schedulingsolution will be described with reference to FIG. 6. An alternativeprocess for identifying a team-specific scheduling solution is describedin section 3 below (with reference to FIG. 7 and FIG. 8)

As described above a work item p has a specified sequence of activities

. Each activity a has an associated work demand

and a maximum limit L being the maximum number of resources that maywork on the activity. A team has a specified iteration sequence (

_(g)) and defined resources (

_(g)), each resource having one or more skills (S_(r)) and availability(

_(rt)) within the iterations of the team.

At 602 the next activity a in the sequence of activities

for the work item is selected.

At 603 an activity specific set of resources is generated. The activityspecific set of resources comprises resources from the team (selected at504) that can contribute to the specific activity (selected at 602). Theability to contribute is based on the skill(s) held by a resource andthe skill(s) required by the activity—if a resource does not have anyskills required by the activity it cannot contribute and is not includedin the activity specific set of resources.

At 604 an ordered queue of solution candidates is generated for thecurrent activity of the work item. Generating the solution candidatequeue for an activity involves generating solution candidates andheuristically ordering them by their solution quality.

A solution candidate for a given activity comprises two components: aresource subset (i.e. a subset of the activity specific set of resourcesgenerated at 603) and a set of iterations in respect of that resourcesubset.

The resource subset of a solution candidate is a subset of resourceswithin the team that have the skills needed to work off the activity.The cardinality of the resource subset is less than or equal to themaximum resource limit for the activity. The number of possible resourcesubsets is exponentially proportional to the total number of resourcesin the activity specific set of resources generated at 603. Where thenumber of resource subsets/solution candidates is manageable from acomputational perspective (i.e. can be processed in an acceptable amountof time), solution candidates for al possible resource subsets aregenerated and considered.

In one embodiment, a solution candidate threshold is introduced to placea limitation on the number of resource subsets (and, accordingly,solution candidates) that are processed/examined. In one implementationthe solution candidate threshold is set at 1000, but alternativethresholds may be used. If the number of possible resource subsets isless than the solution candidate threshold all resource subsets areconsidered. If, however, the number of possible resource subsets exceedsthe solution candidate threshold not all resource subsets areconsidered. Rather, the number of resource subsets (and solutioncandidates) is limited to the threshold, for example by a probabilitybased selection process in which only the threshold number of resourcesubsets is generated.

The set of iterations of a solution candidate includes iterations of theteam that the resources in the solution candidate resource subset arepart of. Each iteration in the set of iterations is associated with aniteration start time and an iteration end time and/or iterationduration. Initially, the set of iterations for each solution candidateis populated with a single iteration, the single iteration being theearliest possible iteration for the team (i.e. the iteration with theearliest start time which is at or after the earliest start time for thetask being scheduled).

The heuristic by which the solution candidates in the queue are orderedis as follows:

-   -   1) A solution candidate with fewer iterations is preferred over        a solution candidate with more iterations (the number of        iterations being the cardinality of the candidate's iteration        set).    -   2) If two or more solution candidates have the same number of        iterations, the solution candidate whose latest iteration in its        iteration set has the earliest end time is preferred.    -   3) If two or more solution candidates have the same number of        iterations and the same earliest end time, the candidate with        the lower heuristic resource cost (discussed below) is        preferred.

The heuristic resource cost is a measure of the value/cost of a givenresource. In one implementation resource cost for a given resource iscalculated to be the sum of the skil costs (described below) for allskills held by that resource.

The skill cost of a particular skill is a measure of how valuable thatskill is. Generally speaking, a skill that is held by many resources isless valuable (and will have relatively low skill cost) than a skillheld by fewer resources. Conversely, a skill that is not held by manyresources is more valuable (and will have a relatively high skill cost).In one embodiment the skill cost of a particular skill held by a givenresource from a given team is heuristically calculated based on thescarcity (or abundance) of that skill across the team. Specifically, theskill cost for a given skill held by a resource is calculated to be1/(the total number of resources in the team who have that skill(including the resource in question)).

At 606 a check is performed to see whether the solution candidate queueis empty. If the solution candidate queue is empty at this stage noscheduling solution for the activity (or, consequently, the work item asa whole) can be found. In this case a message is returned at 608advising that no scheduling solution for the work item could beidentified for the current team.

If the solution candidate queue is not empty at 606, the best solutioncandidate in the queue as identified at 610. As described above, thebest solution candidate is the candidate with the least number ofiterations in its iteration set (i.e. with the lowest iteration setcardinality). If two or more candidates have the same iteration setcardinality, the next best candidate is the candidate whose latestiteration in its iteration set has the earliest end time. If two or morecandidates have the same number of iterations and the same earliest endtime, the first such candidate in the queue is selected.

At 612 an attempt is made to identify an actual assignment of theactivity to the resources of the solution candidate identified at 610.An actual assignment will need to satisfy the work demanded by theactivity and, at the same time, respect the availability constraints ofthe resources in the candidate's resource subset. In one embodiment thisproblem is modeled as a linear program and is solved efficiently usingthe Simplex algorithm. Alternative linear programming algorithms couldbe used.

As noted, a solution candidate is defined by:

-   -   A set or resources        _(s) ⊂        _(g) of a single team gϵ        ; and    -   a set of consecutive iterations        _(s) ⊂        _(g) of this team.

The resulting activity schedule consists of a set of values x_(arts)ϵ

₀ ⁺ quantifying the work of resource r in iteration t with skill s. Toidentify the values the following linear program is solved:

$\begin{matrix}{\min{\sum\limits_{r \in R_{s}}^{\;}\;{W_{r}{\sum\limits_{s \in S_{r}}^{\;}\; x_{rs}}}}} & {{Definition}\mspace{14mu} 24} \\{{{\sum\limits_{s \in S_{r}}^{\;}\; x_{rs}} \leq {\sum\limits_{t \in T_{s}}\;{R_{rt}\mspace{121mu} r}}} \in R_{s}} & {{Definition}\mspace{14mu} 25} \\{{\sum\limits_{r \in R_{s}}^{\;}x_{rs}} = {{D_{as}\mspace{166mu} s} \in S_{a}}} & {{Definition}\mspace{14mu} 26} \\{{x_{rs} \in {{\mathbb{R}}_{0}^{+}\mspace{135mu} r} \in R_{s}},{s \in S_{r}}} & {{Definition}\mspace{14mu} 27}\end{matrix}$

The variables x_(rs) define how much work resource r has to contributewith skill s. The third constraint (definition 26) ensures that the workdemand D_(as) is met for each required skill, whereas the secondconstraint (definition 25) implements the availability limitation overall iterations assigned to the solution candidate. Finally the objectivefunction minimizes the resource cost of for the activity schedule basedon the heuristic resource value. After the overall contributions foreach resource have been calculated corresponding values for eachiteration are identified by finding the values for x_(arts). The highestpossible value for each iteration is then assigned in ascending order.

At 614 a check is performed to determine if an assignment for thecandidate exists (i.e. if the attempt to identify an assignment for thecandidate at 612 was successful).

If an assignment exists, at 616 the assignment is added as the solutionfor the current activity of the work item being processed. Theassignment includes a number of resource assignments, each resourceassignment defining the activity in question, a resource assigned to theactivity (taken from the solution candidate), the iteration(s) in whichthe resource will work on the activity, a resource commitment (e.g.number of story points, hours, or other measure that the resource willspend on the activity in the iteration), and one or more skill(s) thatthe resource will use working on the activity. An assignment alsodefines (or is associated with) a number of iteration violations (0 ormore) taken from the solution candidate.

At 618 a check is then performed to determine whether the work item hasany unscheduled activities.

If unscheduled activities exist at 618 the process returns to 602 toselect the next activity.

If no unscheduled activities exist at 618 all activities of the workitem have been successfully assigned. In this case the identifiedsolution (comprising a set of the assignments of all activities in thework item) is returned at 620 and the process ends.

Returning to the check performed at 614, if no solution for the currentcandidate exists, a check is performed at 622 to determine if thecurrent candidate is still valid. This involves first checking todetermine if the availability of the resources assigned to the solutioncandidate remains constant after the actual iteration(s). If this is notthe case the solution is considered valid until the next test isperformed. If the future availabilities do remain constant a check isthen performed to determine if the limited resources (havingavailability 0 in the future) can satisfy the work demand of theirexclusive skill set (the skills only available in limited resources). Ifthere is no solution for this sub-problem the solution candidate willnot be valid in the future.

If the candidate is determined to be invalid at 622 it is removed fromthe queue of solution candidates at 624. The process then returns to 606to see whether solutions for candidates (if any) that remain in thequeue exist.

If the candidate is determined still to be valid at 622, the candidateremains in the queue but is updated. In updating a candidate theresource selection for the candidate remains the same but the set ofiterations in respect of the candidate is amended.

If, at 622, the candidate is still valid, at 626 a check is performed tosee if the cardinality of the candidate iteration set is greater thanone. If the cardinality of the iteration set is greater than one, theiteration set for the candidate is updated at 628 by adding the team'snext iteration (i.e. the iteration occurring after the last iterationcurrently in the candidate's iteration set) to the candidate's iterationset. This gives the candidate resources more time to perform the workrequired by the activity. The process then returns to 606.

If, at 626, the cardinality of the candidate iteration set equals one, acheck is performed at 630 to determine if the single iteration in thecandidate's iteration set is currently free.

If the single iteration is not free there is the potential that thesubset of resources defined by the candidate could complete the activityin a single iteration if that iteration was free. In this case thecandidate iteration set is updated at 632 by replacing the currentiteration with the team's next iteration and the process returns to 606.

If at 630 the single iteration in the candidate's iteration set is free(i.e. there is no work already booked for the candidate resources inthat iteration) it is determined that the candidate resources cannotcomplete the activity in a single iteration. In this case the candidateiteration set is updated by adding the next iteration to the set at 628before the process returns to 606.

Having an activity extend across multiple iterations reduces the qualityof the solution candidate significantly. A solution candidate with morethan one iteration in its iteration set will only be considered if thereare no solution candidates in the queue which can potentially completethe activity in a single iteration (i.e. have an iteration set with acardinality of one).

2.2 Iteration Aware Scheduling Clauses

Described herein is a computer implemented scheduling method comprising:accessing project data from computer readable storage media, the projectdata comprising: work item data defining a plurality of work items to bescheduled; resource data defining a plurality of resources; team datadefining a plurality of teams, each team made up of one or moreresources and having a schedule of iterations; for each work item:processing, using a computer processor, the project data to determineone or more team-specific scheduling solutions for the work item, eachteam specific scheduling solution for the work item defining aparticular team and one or more iterations of that particular team inwhich the work item can be completed; identifying from the one or moreteam-specific scheduling solutions an optimal scheduling solution forthe work item, the optimal scheduling solution being selected based atleast in part on the number of iterations defined by each of the one ormore team-specific scheduling solutions; and scheduling the work itemaccording to the optimal scheduling solution identified for the workitem.

An optimal scheduling solution may be determined to be a team-specificscheduling solution defining the fewest number of iterations.

If multiple team-specific scheduling solutions define a same leastnumber of iterations, the optimal scheduling solution may be determinedto be the team-specific scheduling solution which defines the leastnumber of iterations and an earliest work item completion time.

Processing the project data to determine one or more team-specificscheduling solutions for a given work item may comprise; for each teamavailable to work on the given work item, processing the project data totry and determine a team-specific scheduling solution for the given workitem for that team.

Each work item may comprise one or more work item activities, andwherein processing the project data to determine a team-specificscheduling solution in respect of a given work item and a given team maycomprise: processing the project data to determine a final assignmentfor each activity of the given work item, the team specific schedulingsolution for the given work item comprising the final assignments forall activities of the given work item, and wherein a final assignment inrespect of a particular activity of the given work item defines asub-team of the given team and one or more iterations in which thesub-team can complete the particular activity of the given work item.

Determining a final assignment for a given activity of a given work itemfor a given team may comprise: generating a queue of solutioncandidates, each solution candidate defining a sub team of the giventeam and one or more iterations; determining a heuristic solutionquality for each solution candidate in the queue of solution candidates;selecting a current solution candidate from the queue of solutioncandidates, the current solution candidate being the solution candidatewith the best heuristic solution quality, determining whether anassignment for the given activity and current solution candidate exists;and responsive to determining that an assignment for the given activityand current solution candidate exists, determining that assignment to bethe final assignment for the given activity; or responsive todetermining that no assignment for the given activity and currentsolution candidate exists, attempting to determine an assignment for thegiven activity and a different or updated solution candidate.

The heuristic solution quality for a given solution candidate may bebased on the number of iterations defined by the given solutioncandidate and an end time of a latest iteration defined by the solutioncandidate.

The method may further comprise processing the project data to identifyand remove from further processing work items that cannot be scheduled.

The project data may further comprise dependency data defining one ormore dependency relationships between work items, and whereinidentifying and removing work items that cannot be scheduled maycomprise processing the dependency data to identify and remove workitems with cyclic dependencies.

Identifying and removing work items that cannot be scheduled may furthercomprise identifying and removing work items which are dependent on awork item with a cyclic dependency.

The project data may further comprise: work item skill data defining,for a given work item, one or more skills required in order to completethe given work item, and resource skill data further defines, for agiven resource, one or more skills held by the given resource; andwherein identifying and removing work items that cannot be scheduled maycomprise processing the project data to identify and remove any workitems that require at least one skill that is not held by any resource.

The method may further comprise processing the project data to identifyand remove from further processing resources that cannot contribute tothe completion of any work item.

The project data may further comprise: work item skill data defining,for a given work item, one or more skills required in order to completethe given work item, and resource skill data further defines, for agiven resource, one or more skills held by the given resource; andwherein identifying and removing resources that cannot contribute to thecompletion of any work item may comprise processing the project data toidentify and remove any resource that does not hold one or more skillsrequired by any work item.

Also described herein is a system comprising: one or more processors;one or more non-transitory computer-readable storage media storingsequences of instructions which, when executed by the one or moreprocessors, cause the one or more processors to perform the a method asdescribed in the preceding paragraphs.

3. Automatic Assignment of Work Items to Team Resources

In the iteration aware scheduling process described above, attempting toschedule a selected work item (process 206 described with reference toFIG. 5) involves attempting to identify a team-specific schedulingsolution for the work item (process 506 described with reference to FIG.6). A team specific scheduling solution for a work item is a solutionwhereby the work item is assigned to one or more members of the specificteam (not necessarily the whole team). Process 506, in turn, involvesidentifying solution candidates (at 602).

As noted, the number of potential solution candidates growsexponentially with the number of resources in the team being considered.This is due to the fact that if there is a team with n resources havingat least one skill required for the work item, and a maximum resourceconstraint (L—being the total number of resources that can work on thework item) of k, the number of possible resources assignments is “nchoose k”. Practically speaking this prohibits the complete examinationof the solution space.

In order to limit the solution space the number of solution candidatesis limited to a solution candidate threshold. This section describes analternative computer implemented process identifying a team-specificscheduling solution for a work item that uses probabilistic sampling toselect solution candidates and, ultimately, allocate resources to workitems.

3.1 Computer Implemented Method for Automatically Assigning Work Itemsto Team Resources

FIG. 7 provides a flowchart 700 depicting processing to identify a teamspecific scheduling solution for a work item in accordance with anembodiment. The processing described in this section and shown in FIG. 7provides an alternative process for identifying a team specificscheduling solution to process 506 described above with respect to FIG.6.

As with process 506, the inputs to process 700 comprises a particularwork item p (selected at 204), a team g (selected at 504) for which ascheduling solution for the work item is to be identified, and a timerange (defined at 502). The work item p has a sequence of activities

, each activity a in the sequence having an associated work demand

_(as) and a maximum constraint limit L (the maximum number of resourcesthat may work on the activity). A team has a specified iterationsequence (

_(g)) and defined resources (

_(g)), each resource having one or more skills (S_(r)) and availability(

_(rt)) within the iterations of the team.

At 702 the next activity a in the sequence of activities

for the work item is selected.

At 703 an activity specific set of resources is generated. The activityspecific set of resources comprises resources from the team (selected at504) that can contribute to the specific activity (selected at 602). Theability to contribute is based on the skill(s) held by a resource andthe skill(s) required by the activity—if a resource does not have anyskills required by the activity it cannot contribute and is not includedin the activity specific set of resources.

At 704 a set of potential iterations in respect of the activity isgenerated. This involves identifying iterations of the team in questionthat have a start time on or after the earliest start time for theactivity and an end time before or at the latest end time of theactivity.

At 706 a check is performed to determine if there a next iterationexists in the set of potential iterations identified at 704. If not, allpotential iterations have been checked for the activity and no schedulehas been identified. In this case a message indicating no solution wasfound is returned at 708 and process 700 ends.

If a next iteration does exist at 706, this iteration is selected at710. The next iteration is the iteration with the earliest start time.

At 712 a set of solution candidates for working off the activityselected at 702 in the iteration selected at 710 is generated. In thisimplementation the set of solution candidates is a priority queue, butalternative data structures for storing solution candidates withassociate priority could be used. Processing to generate the set ofsolution candidates at 712 is described in further detail below withreference to FIG. 8.

Generally speaking, the solution candidates in the set are considered inturn according to their associated priorities. An attempt to identify anassignment of the activity to the solution candidate is made and, ifsuccessful, that assignment is accepted. If not the next solutioncandidate in the set is considered.

At 714 a check is performed to see whether the solution candidate queueis empty. If the solution candidate queue is empty the process returnsto 706 to determine whether a next iteration exists that can be checked.

If the solution candidate queue is not empty at 714, the next solutioncandidate in the queue is identified at 716 (based on the solutioncandidate priority).

At 718 an attempt is made to identify an actual assignment of theactivity to the solution candidate identified at 716. Attempting toidentify an assignment of the activity to the solution candidate is thesame process as described above with respect to processing stage 612 ofprocess 506.

At 720 a check is performed to determine if an assignment for thesolution candidate exists. If no assignment is returned by 718 theprocess returns to 714 to determine whether other solution candidatesexist.

If an assignment for the candidate does exist, at 722 the assignment isadded as the solution for the current activity of the work item beingprocessed.

At 724 a check is then performed to determine whether the work item hasany unscheduled activities. If unscheduled activities exist the processreturns to 702 to select the next activity.

If no unscheduled activities exist at 724 all activities of the workitem have been successfully assigned. In this case the identifiedsolution (comprising a set of the assignments of allactivities/resources in the work item) is returned at 726 and process700 ends. Each assignment defines the activity in question, a resourceassigned to the activity (taken from the solution candidate), theiteration(s) in which the resource will work on the activity, a resourcecommitment (e.g. the number of story points, hours, or other measure)indicating how much work the resource is assigned to work on theactivity in the iteration, and one or more skill(s) that the resourcewill use working on the activity. An assignment also defines (or isassociated with) an iteration count taken from the solution candidate.

When performing the check at 512 to determine whether a given solutionis the best or optimal solution so far the iteration count is treatedsimilarly to the iteration violations described above. The number ofiteration violations is equal to the iteration count minus 1 (i.e. aniteration count of 1 does not indicate any iteration violations as thework is completed in a single iteration, whereas an iteration count of 2indicates a single iteration violation). I.e.

-   -   1) The solution returned at 506 is preferable to the current        optimal solution if it has a lower iteration count;    -   2) If the iteration count of the solution returned at 506 is        equal to the iteration count of the current optimal solution,        the solution returned at 506 will be preferable if it has an        earlier end date.

Solution Candidate Queue Generation: 712

At 712 of process 700 the data is processed to generate set of solutioncandidates. In this example the set of solution candidates is a priorityqueue. This processing will be described with reference to FIG. 8.

As discussed above, a solution candidate is a subset of resourcesselected from the activity specific set of resources (selected at 703)that will be considered to work off a particular activity (selected at702) in one or more iterations (selected at 710).

The data processed in order to generate individual solution candidatesand the priority queue of solution candidates comprises: the set ofskills s required to work off the activity a being considered (

_(as)); the resources r in the activity specific set of resourcesgenerated at 703; the skills s of each resource r (S_(r)); theavailability of each resource in the iteration t being considered(R_(rt)); the maximum number of resources r permitted to work on theactivity a (L); and the threshold number of solution candidates to begenerated (n). As noted above, in one implementation the thresholdnumber of solution candidates is 1000.

Two aspects are considered when processing the data to select a subsetof resources for a solution candidate:

-   -   1) Skills: the subset of resources for a solution candidate must        have the skills required to work off the activity.    -   2) Availability: resources with higher availability in the        particular iteration are preferable+.

The first of these aspects (selecting a subset of resources from theparticular team that have the requisite skill(s) to work off theactivity) is a set cover problem (SCP). The set cover problem is knownto be NP-complete and as such is not efficiently solvable for largeproblem instances.

In order to address this, the present method introduces a probabilisticsampling method for selecting resources to be added to the subset ofresources for a given solution candidate. Resources to be added to theresource subset for a solution candidate are selected in turn bysampling the set of available resources for the solution candidate. Twodifferent sampling methods are used: one that selects a resource basedon skills and one that selects a resource based on availability.Furthermore, in order to improve robustness, the probability of one orthe other sampling method being used to select a resource is weightedaccording to which solution candidate is being generated.

In process 800 a candidate index i is maintained to record whichparticular solution candidate (out of the threshold number n of solutioncandidates) is currently being generated. At 802 the candidate index iis initialized to indicate that the first solution candidate is beinggenerate (e.g. i=1).

At 804 a check is performed to determine whether further solutioncandidates need to be generated. If the candidate index i indicates thatthe threshold number of solution candidates have been generated (e.g.i>n) no further candidates are required and at 806 the priority queue ofsolution candidates is returned. If further solution candidates do needto be generated, the process proceeds to 808.

Generating a solution candidate involves selecting k resources that willmake up the resource subset for the candidate, k is the maximum numberof resources permitted to work on the activity in question which, inturn, is based on the maximum number of resources permitted to work onthe work item which the activity is part of −L). In order to generate agiven solution candidate i, a resource index j is maintained to trackthe number of resources that have been generated. At 808 j isinitialized to indicate the first resource for the resource subset isbeing selected (e.g. j=1).

At 810 a check is performed to determine whether further resources needto be selected for the resource subset. If the resource index jindicates that the maximum number of resources have been selected (i.e.j>k) no further resources need to be selected.

If, at 810, no further resources need to be selected an iteration setfor the solution candidate is generated. The iteration set defines theiterations assigned to the solution candidate. The iterations for thesolution candidate include all iterations between (and including) thelast free iteration for the solution candidate's resource subset (i.e.the last iteration in which all resources selected for the candidatewere free) and the current iteration (selected at 710) for which thesolution candidate priority queue is being generated. An iteration countis also calculated for the solution candidate, the iteration count beingthe number of iterations in the iteration set. As described above, theiteration count is used at 512 to determine the quality of one solutioncandidate compared to another.

At 814 the solution candidate i is added to the solution candidatepriority queue. The priority of the new solution candidate being addedto the queue is determined according to the following:

-   -   1) If the new solution candidate has a lower iteration count        than an existing solution candidate the new solution candidate        is assigned a higher priority.    -   2) If the new solution candidate has the same iteration count as        an existing solution candidate, the solution candidate with the        lower skill cost has a higher priority.

The skill cost of a given solution candidate is the sum of the resourcecosts of the resources in that solution candidate. As described above,the resource cost of a resource is a measure of the value/cost of thatresource and is, in turn, calculated as the sum of the skill costs ofall skills held by that resource. The calculation of skill costs isdescribed above.

At 816 the candidate index i is incremented (e.g. i=i+1) and the processreturns to 804 to determine whether further solution candidates need tobe generated.

If, at 810, further resources do need to be selected, the samplingmethod to be used to select the next resource is determined at 818.

In the present embodiment a resource can be selected using one of twosampling methods.

The first sampling method is a skill based sampling method. Given theskills demanded by the activity and the skills provided by a partialsolution to the activity, the skill based sampling method seeks toselect the resource that provides the most demanded but not yet providedskills. Ties are resolved randomly.

The skill based sampling method can be illustrated by the followingexample. Consider: an activity requiring skills {1, 2, 3}; availableresources are {A, B, C}; the skills of resource A S_(A)={1, 2}; theskills of resource B S_(B)=(2); and the skills of resource C S_(C)={3}.Initially, the required skills are {1, 2, 3} so resource A is selectedbecause it has two of the required skills (versus resources B and Cwhich each only have 1 of the required skills). Following this, theremaining skills required are {3}, leading to resource C being selectedas it has one of the required skills (versus resource B who has 0 of therequired skills).

The second sampling method is an availability based sampling method. Inone embodiment the availability based sampling method involvesimplementing a roulette-wheel (or fitness proportionate) selectionprocess in which selection of a resource is based on the availabilityvalue of the resource in the iteration being considered. Using thisapproach the likelihood of a resource being selected is directlyproportional to the availability of that resource within the iterationdivided by the overall availability of the other available resources forthe iteration. For example, if the availability of a particular resourcewithin an iteration is 10 time units, and the total availability of theall resources available within the iteration is 200 time units, theprobability of the particular resource being selected is

$\frac{10}{200} = {0.05.}$

In order to improve robustness of the resource selection the skill andavailability based sampling methods are heuristically combined. In thepresent implementation this involves probabilistically selecting thesampling method to be used to select the next resource at 816. Theprobability p of using the skill based sampling method is calculatedbased on the index i of the solution candidate currently being generated(i.e. the solution candidate for which a resource is being selected) andthe total number n of solution candidates that are to be generated:p=i/n. The probability of using the availability based sampling methodto select a resource is 1−p.

Calculating p in this manner results in the skill based sampling methodbeing less likely to be used when selecting resources for earliergenerated solution candidates (i.e. solution candidates being generatedearlier in the queue generation process 712) and more likely to be usedwhen selecting resources for later generated solution candidates (i.e.solution candidates being generated later in the queue generationprocess 712). Put conversely, calculating p in this manner results inthe availability based sampling method being more likely to be used whenselecting resources for earlier generated solution candidates and lesslikely to be used when selecting resources for later generated solutioncandidates.

For example, consider a process with a threshold number of solutioncandidates of n=1000. During generation of the first solution candidate(i=1): the probability of selecting a resource using the skill basedsampling method is

$\frac{i}{n} = 0.001$and the probability of selecting a resource using the availability basedsampling method is

$\left( {1 - \frac{i}{n}} \right) = 0.999$During generation of the 500^(th) candidate (i=500) the probabilities ofselecting a resource using the skill based sampling method and theavailability based sampling method are the same:

${\frac{i}{n} = 0.05},{\left( {1 - \frac{i}{n}} \right) = {0.5.}}$

Following selection of the resource sampling method at 818, the selectedsampling method is used to select a resource at 820.

At 822 the resource selected at 820 is added to the current solutioncandidate.

At 824 the resource index j is incremented (e.g. J=j+1) and the processreturns to 810 to determine whether further resources need to beselected for the current solution candidate.

3.2 Automatic Assignment of Work Items to Team Resources Clauses

Described herein is a computer implemented method comprising: accessingproject data from computer readable storage media, the project datacomprising: work item data defining a work item; activity data definingone or more activities that form part of the work item; team datadefining a team of resources; a maximum resource constraint defining amaximum number of resources able to work on the work item; a solutioncandidate threshold defining a maximum number of solution candidates;for the or each activity forming part of the work item: processing,using a computer processor, the project data to generate a set ofsolution candidates for the activity; selecting a solution candidatefrom the set of solution candidates; processing the project data toattempt to identify an assignment of the activity to the selectedsolution candidate; and responsive to identifying an assignment of theactivity to the selected solution candidate, assigning the activity tothe selected solution candidate, wherein: a solution candidate comprisesa subset of resources from the team of resources; generating a set ofsolution candidates for an activity comprises generating a number ofsolution candidates which is less than or equal to the solutioncandidate threshold; generating a given solution candidate comprisesselecting a number of resources for inclusion in the subset of resourcesfor that solution candidate, the number of resources being equal to themaximum resource constraint; and selecting a given resource forinclusion in a solution candidate subset comprises: selecting a samplingmethod; using the selected sampling method to select a resource from theteam of resources.

Selecting a sampling method may comprise probabilistically selecting asampling method.

Selecting a sampling method may comprise probabilistically selectingeither a first sampling method or a second sampling method.

A probability of selecting the first sampling method may be weightedaccording to an index of the solution candidate being generated.

The first sampling method may be a skill based sampling method.

The activity data may further define, for the or each activity, skillsrequired to complete the activity; the project data may further compriseresource data, the resource data defining, for each resource, one ormore skills held by the resource; and wherein the skill based samplingmethod may involve selecting a resource which holds skills that are mostdemanded by the activity but not yet provided by any other selectedresource.

The second sampling method may be an availability based sampling method.

The project data may further comprise resource data, the resource datadefining, for each resource, availability of the resource; and theavailability based sampling method may involve selecting a resource fromthe team of resources based on an availability of that resource relativeto availability of other resources in the team of resources.

Generating a given solution candidate may further comprise calculating apriority in respect of the solution candidate, and selecting a solutioncandidate comprises selecting the solution candidate with the highestpriority.

Responsive to not identifying an assignment of the activity to theselected solution candidate, the method may further comprise: selectinga further solution candidate from the set of solution candidates;processing the project data to attempt to identify an assignment of theactivity to the further solution candidate; and responsive toidentifying an assignment of the activity to the further solutioncandidate, assigning the activity to the second solution candidate.

The team data may further define one or more iterations in which theteam works; a set of solution candidates for a given activity maygenerated for a particular iteration of the team; and if no assignmentof the given activity to any of the solution candidates in a set ofsolution candidates is possible, the method may further comprise:generating a further set of solution candidates for the given activityusing a next iteration of the team; selecting a solution candidate fromthe further set of solution candidates; processing the project data toattempt to identify an assignment of the activity to the selectedsolution candidate; and responsive to identifying an assignment of theactivity to the selected solution candidate, assigning the activity tothe selected solution candidate.

Also described herein is a system comprising: one or more processors;one or more non-transitory computer-readable storage media storingsequences of instructions which, when executed by the one or moreprocessors, cause the one or more processors to perform the a method asdescribed in the preceding paragraphs.

4. Release Aware Scheduling

Section 2 above describes iteration aware scheduling methods/processeswhich schedule work items taking into account the iterations in whichteams work. In the embodiment described the release aware schedulingextends the iteration aware scheduling described in sections 2 and 3above to schedule work items while taking releases (e.g. projectmilestones, software releases, or other deliverables) into account. Inalternative embodiments features and/or principles of the release awarescheduling may be used in conjunction with other schedulingmethods/processes.

4.1. Release Aware Scheduling Problem Description

In the present embodiment the release aware scheduling process describedherein extends the iteration aware scheduling described in sections 2and 3 above. Accordingly, the data/concepts described in relation to theiteration aware scheduling process are also relevant to the releaseaware scheduling problem.

In addition to the data/concepts described above, the release awarescheduling problem takes into account releases. A release is denoted eand the set of all releases is denoted E (eϵE).

In order to schedule tasks taking into account releases, release starttimes and end times need to be considered.

The start time for a release may be a fixed (or not earlier than) starttime—e.g. release n is to start at the earliest at time x.Alternatively, a release may have a start time dependent on apredecessor release—e.g.: release version 2.0 can start only afterrelease version 1.0 is complete; work on milestone 2 can only start 2weeks after milestone 1 is complete (e.g. so customers can give feedbackon milestone 1); work on release version 2 can start up to 4 weeksbefore the estimated/scheduled end time of release work 1.0.

An end time for a release (i.e. the date/time by which all work itemsnecessary to the release must be complete) may be a fixed end time—e.g.release 1.0 must be complete by time x. In this case the schedulingmethod described herein operates to suggest work items that can be fitinto the scope of the release (i.e. work items that can be completed bythe fixed end time). Alternatively, a release can have a non-fixed ordynamic end time. In this case the scheduling method described in thissection operations to forecast an end time for the release taking intoaccount work items that are essential to that release (i.e. work itemsthat have been flagged as must-have deliverables for the release).

Two types of releases e are considered/distinguished: preferred end timereleases and fixed scope releases.

A preferred end time release is a release with a preferred end timeet_(e)ϵ[0, {tilde over (T)}].

A fixed scope release does not have a preferred end time. Instead, asubset of the work items is strictly assigned to the release such thatthose work items must be included in the release.

These two types of releases mirror two problems in release scheduling,namely how much can be done until a defined deadline is reached and howlong does it take to work off a given set of requirements.

The model described herein allows a release to be to have both apreferred end time and a fixed scope. In this case the work itemsstrictly assigned to the release take precedence and the preferred endtime assigned to the release may be exceeded (with an appropriate alert)in order to ensure all assigned work items are completed within therelease.

The start date of a release may either be fixed or dependent in some wayon a preceding release. The predecessor of a release is denoted e^(<).This precedence relation is strictly linear and cannot involve acircular dependency.

Where a predecessor is defined so too is a start-time gap δ_(e) (δ_(e)ϵ

). The start-time gap defines how many time steps are allowed betweenthe end of a predecessor release and the start of a release dependent onthat predecessor release. The start-time gap may define a negativenumber of time steps.

For each work item/release pair a constant Y_(pe) (Y_(pe)ϵ{0,1}) isprovided which defines whether the work item p has to be scheduled inthe release e. This assignment is assumed to be exclusive, so for allwork items Σ_(eϵE) y_(pe)≤1.

In order to incorporate releases into the mixed integer linear program,certain of the definitions in the iteration aware scheduling problemdescription above (section 2.1) are modified and additional definitionsare provided. These modifications and additions are described below.Where a definition is either the same as or a modified version of adefinition provided in the iteration aware scheduling problem the samedefinition number is used. Where a definition is new/specific to therelease aware scheduling problem a new definition number is provided. Todistinguish between the definitions in this section and the definitionsin the iteration aware scheduling section above definitions in thissection are denoted with a prime (′) character.

Work Constraints

In order to incorporate releases the decision variable described in theiteration aware scheduling problem above is extended to take theassigned release into account. This is shown in the work constraints ofdefinitions 1′ and 2′ below.

$\begin{matrix}{{x_{earts} \in {\mathbb{R}}_{0}^{+}}{{e \in E},{a \in \mathcal{A}},{r \in \mathcal{R}},{t \in \mathcal{T}_{r}},{s \in \mathcal{S}_{ar}}}} & {{Definition}\mspace{14mu} 1^{\prime}} \\{{{\sum\limits_{e \in E}\;{\sum\limits_{a \in \mathcal{A}}\;{\sum\limits_{s \in \mathcal{S}_{ar}}\; x_{earts}}}} \leq \mathcal{R}_{rt}}{{r \in \mathcal{R}},{t \in \mathcal{T}_{r}}}} & {{Definition}\mspace{14mu} 2^{\prime}}\end{matrix}$

Work Demand

Similar to the iteration aware scheduling problem above, optional workitems are considered. This consideration is extended by defining thesevalues for every release as per definitions 3′, 28′, and 4′ below:

$\begin{matrix}{{y_{pe} \in \left\{ {0,1} \right\}}{{p \in \mathcal{P}},{e \in E}}} & {{Definition}\mspace{14mu} 3^{\prime}} \\{{y_{pe} \geq Y_{pe}}{{p \in \mathcal{P}},{e \in E}}} & {{Definition}\mspace{14mu} 28^{\prime}} \\{{{\sum\limits_{r \in \mathcal{R}}\;{\sum\limits_{t \in \mathcal{T}_{r}}\; x_{earts}}} = {y_{pe}*\mathcal{D}_{as}}}{{a \in \mathcal{A}},{s \in \mathcal{S}_{a}},{e \in E}}} & {{Definition}\mspace{14mu} 4^{\prime}}\end{matrix}$

Resource Assignment

In order to take releases into account minor changes are made to thecoupling constraint (definition 6′) described in the iteration awarescheduling problem above.

$\begin{matrix}{{y_{ar} \in \left\{ {0,1} \right\}}{{a \in \mathcal{A}},{r \in \mathcal{R}}}} & {{Definition}\mspace{14mu} 5^{\prime}} \\{{{y_{ar}*M} \geq {\sum\limits_{e \in E}\;{\sum\limits_{t \in \mathcal{T}_{r}}\;{\sum\limits_{s \in \mathcal{S}_{r}}\; x_{earts}}}}}{{a \in \mathcal{A}},{r \in \mathcal{R}}}} & {{Definition}\mspace{14mu} 6^{\prime}} \\{{{\sum\limits_{r \in \mathcal{R}}\; y_{ar}} \leq L_{a}}{a \in \mathcal{A}}} & {{Definition}\mspace{14mu} 7^{\prime}}\end{matrix}$

Team Assignment

This is also the case for the team assignment constraint, with minorchanges in definition 9′.

$\begin{matrix}{{y_{pg} \in \left\{ {0,1} \right\}}{{p \in \mathcal{P}},{g \in \mathcal{G}}}} & {{Definition}\mspace{14mu} 8^{\prime}} \\{{{y_{pg}*M} \geq {\sum\limits_{e \in E}\;{\sum\limits_{a \in \mathcal{A}}\;{\sum\limits_{r \in \mathcal{R}_{g}}\;{\sum\limits_{t \in \mathcal{T}_{r}}\;{\sum\limits_{s \in \mathcal{S}_{ar}}x_{earts}}}}}}}{{p \in \mathcal{P}},{g \in \mathcal{G}}}} & {{Definition}\mspace{14mu} 9^{\prime}} \\{{{\sum\limits_{g \in \mathcal{G}}\; y_{pg}} \leq 1}{p \in \mathcal{P}}} & {{Definition}\mspace{14mu} 10^{\prime}}\end{matrix}$

Dependencies

The coupling constraint of activity/iteration assignments is updated(definition 12′) to adapt both the causal precedence constraints and theearliest start definition.

$\begin{matrix}{{y_{at} \in \left\{ {0,1} \right\}}{{a \in \mathcal{A}},{t \in \mathcal{T}}}} & {{Definition}\mspace{14mu} 11^{\prime}} \\{{{y_{at}*M} \geq {\sum\limits_{e \in E}\;{\sum\limits_{r \in \mathcal{R}}\;{\sum\limits_{s \in \mathcal{S}_{ar}}x_{earts}}}}}{{a \in \mathcal{A}},{t \in \mathcal{T}}}} & {{Definition}\mspace{14mu} 12^{\prime}} \\{{{st}_{a} \in \left\lbrack {0,\overset{\_}{T}} \right\rbrack}{a \in \mathcal{A}}} & {{Definition}\mspace{14mu} 13^{\prime}} \\{{{st}_{a} \leq {y_{at}*{ST}_{t}}}{{a \in \mathcal{A}},{t \in \mathcal{T}}}} & {{Definition}\mspace{14mu} 14^{\prime}} \\{{{et}_{a} \in \left\lbrack {0,\overset{\_}{T}} \right\rbrack}{a \in \mathcal{A}}} & {{Definition}\mspace{14mu} 15^{\prime}} \\{{{et}_{a} \leq {y_{at}*{ET}_{t}}}{{a \in \mathcal{A}},{t \in \mathcal{T}}}} & {{Definition}\mspace{14mu} 16^{\prime}} \\{{{{et}_{a_{1}} + 1} \leq {{st}_{a_{2}}\left( {a_{1},a_{2}} \right)}} \in ɛ} & {{Definition}\mspace{14mu} 17^{\prime}}\end{matrix}$

Earliest Startst_(α)≥EST_(α) αϵ

  Definition 18′

Releases

A similar scheme as for start and end times of activities is introducedin order to incorporate the release characteristics.

Accordingly, a new set of binary decision variables is introduced toindicate that work on a given release is done in an iteration and toderive start and end times (definitions 29′ to 34′ below).

Constraints are then defined that ensure that the defined earliest startdate and the preceding release gaps are respected (definitions 35′ and36′ respectively)

$\begin{matrix}{{y_{et} \in \left\{ {0,1} \right\}}{{e \in E},{t \in \mathcal{T}}}} & {{Definition}\mspace{14mu} 29^{\prime}} \\{{{y_{et}*M} \geq {\sum\limits_{e \in E}\;{\sum\limits_{r \in \mathcal{R}}\;{\sum\limits_{s \in \mathcal{S}_{ar}}x_{earts}}}}}{{e \in E},{t \in \mathcal{T}}}} & {{Definition}\mspace{14mu} 30^{''}} \\{{{st}_{e} \in \left\lbrack {0,\overset{\_}{T}} \right\rbrack}{e \in E}} & {{Definition}\mspace{14mu} 31^{\prime}} \\{{{st}_{e} \leq {y_{et}*{ST}_{t}}}{{e \in E},{t \in \mathcal{T}}}} & {{Definition}\mspace{14mu} 32^{\prime}} \\{{{et}_{e} \in \left\lbrack {0,\overset{\_}{T}} \right\rbrack}{e \in E}} & {{Definition}\mspace{14mu} 33^{\prime}} \\{{{et}_{e} \leq {y_{et}*{ET}_{t}}}{{e \in E},{t \in \mathcal{T}}}} & {{Definition}\mspace{14mu} 34^{\prime}} \\{{{st}_{e} \leq {ST}_{e}}{e \in E}} & {{Definition}\mspace{14mu} 35^{\prime}} \\{{st}_{e} \in {{et}_{e^{\prec}} + {\delta_{e}\left( {e^{\prec},e} \right)}}} & {{Definition}\mspace{14mu} 36^{\prime}}\end{matrix}$

Release Aware Scheduling Optimization

The hierarchy of objective functions is similar to the hierarchy in theiteration aware scheduling optimization described above. In decreasingimportance:

-   -   1) Work flow    -   2) Release date violations    -   3) Work item (story) value    -   4) Weighted completion times

Work Flow

The topmost priority of ensure a structured work flow by minimizing thenumber of iteration violations remains unchanged:

$\begin{matrix}{\min{\sum\limits_{a \in \mathcal{A}}\;{\sum\limits_{t \in \mathcal{T}}\; y_{at}}}} & {{Definition}\mspace{14mu} 19^{\prime}}\end{matrix}$

Release Date Violation

Adaptations are made to the model to account for the incorporation ofmultiple releases.

Initially, the delay indicator function is changed to be releasespecific, per definition 37′ below:

$\begin{matrix}{Y_{et} = \left\{ \begin{matrix}{1,} & {{{if}\mspace{14mu}{ET}_{t}} > {ET}_{e}} \\{0,} & {otherwise}\end{matrix} \right.} & {{Definition}\mspace{14mu} 37^{\prime}}\end{matrix}$

Following this the sum of all release date delays is minimized (vreferring to iteration violations):

$\begin{matrix}{\min{\sum\limits_{e \in E}\; x_{e}^{v}}} & {{Definition}\mspace{14mu} 38^{\prime}} \\{{x_{e}^{v} \geq {y_{et}*Y_{et}*E_{t}}}{{e \in E},{t \in \mathcal{T}}}} & {{Definition}\mspace{14mu} 39^{\prime}} \\{{x_{e}^{v} \in \left\lbrack {0,\overset{\_}{T}} \right\rbrack}{e \in E}} & {{Definition}\mspace{14mu} 40^{\prime}}\end{matrix}$

This is only needed if at least one work item is strictly scheduled. Ifno work items are strictly scheduled the constraint of definition 41′ isadded:x^(v)=0  Definition 41′

Work Item (Story) Value

The work item objective function does not need any adaptations, so is asper the iteration aware scheduling section above.

$\begin{matrix}{\max{\sum\limits_{p \in \mathcal{P}}\;{y_{p}*\mathcal{W}_{p}}}} & {{Definition}\mspace{14mu} 20^{\prime}}\end{matrix}$

Weighted Completion Times

The weighted completion times objective also remains the same:

$\begin{matrix}{\min{\sum\limits_{p \in \mathcal{P}}{{et}_{p}*\mathcal{W}_{p}}}} & {{Definition}\mspace{14mu} 21^{\prime}} \\{{{et}_{p} \geq {et}_{a}}{{p \in \mathcal{P}},{a \in \mathcal{A}_{p}}}} & {{Definition}\mspace{14mu} 22^{\prime}} \\{{{et}_{p} \in \left\lbrack {0,\overset{\_}{T}} \right\rbrack}{p \in \mathcal{P}}} & {{Definition}\mspace{14mu} 23^{\prime}}\end{matrix}$

4.2 Release Aware Scheduling Method

This section provides describes a computer implemented method forautomatically scheduling project tasks taking releases (as well as theiterations in which teams work) into account. The method is implementedby a computer processing system, one example of which is describedbelow.

The method described in this section extends the iteration awarescheduling method described in section 2.2 above. Accordingly, thissection will focus on the differences/additional processing.

To illustrate the release aware scheduling embodiment, Table 4 belowprovides an example of a table used to capture/store data relating toresources. This is similar to Table 1 of the iteration aware schedulingdescribed above.

TABLE 4 Resources Weekly Hours Team Team Resource Available Absent InTeam Skills Schedule A Member A Always None 40 1 Scrum (2 weeks) AMember B Always None 20 1, 2 B Member C Always None 32 3 Scrum (3 weeks)B Member D Always None 40 1, 2, 3 B Member B Always None 20 1, 2 CMember D Always None 40 1, 2, 3 Scrum C Member E Always None 40 3 (2weeks), Starting sprints on Tuesdays.

Table 5 below is an example of a table used to capture/store datarelating to releases. In this example each release can have a targetstart date and a target end date and a scheduled (actual) start date anda scheduled (actual) end date. The scheduled start and end dates arecalculated by the release aware scheduling method described in thissection.

TABLE 5 Releases Release Target Target Scheduled Scheduled Name StartEnd (Actual) Start (Actual) End R1 1 Jan. 31 Jan. (Calc) (Calc) 20152015 R2 Up to 2 28 Feb. (Calc) (Calc) weeks before 2015 R1 ends

Table 6 is an example of a table used to capture/store data relating towork items. Table 6 is similar to table 2 above, however in table 6includes a release field indicating allowing a user to specify that aparticular work item must be included in a particular release (e.g. intable 2 work item A1.1 has been specified for inclusion in release 2.

TABLE 6 Work items Work Earliest Depends Sched Sched Est Skill SkillSkill item Team Release Start on start end (h) 1 2 3 Priority Project A(Calc) (Calc) (Calc) 290 95 45 150 A A.1 (Calc) (Calc) (Calc) 290 95 45150 A A.1.1 Team B R2 (Calc) (Calc) 100 100 1 A A.1.2 Team C (Calc)(Calc) (Calc) 40 20 20 2 A A.1.3 (Calc) (Calc) (Calc) (Calc) 50 50 3 AA.1.4 (Calc) (Calc) (Calc) (Calc) 100 25 25  50 4 A

FIG. 9 provides a flowchart 900 which depicts the high level stagesinvolved scheduling tasks taking into account release (and iterations).Each of the high level stages represented by flowchart 900 will bedescribed in detail following the general description.

At 902, preprocessing is performed. At 904, scheduling of strictlyassigned work items is performed. A strictly assigned work item is awork item that is required to be completed in a particular release. Inorder to schedule strictly assigned work items any causal predecessorwork items to the strictly assigned work items also need to bescheduled.

At 906, scheduling of unconstrained release work items is performed. Anunconstrained release work item is a work item in the backlog that hasnot been strictly assigned to a particular release and is not a causalpredecessor to a strictly assigned work item.

Once the release aware scheduling process is complete the schedulecalculated is presented to a user. The tables described above may beused to present scheduling information to a user by populating thefields calculated by the release aware scheduling method. This isillustrated in table 9 (in which the scheduled/actual start and enddates for the releases are shown) and table 8 (in which the scheduledstart dates for the work items are shown), tables 9 and 8 following fromthe examples provided in tables 4, 5 and 6 above.

TABLE 9 Releases following release aware scheduling process ReleaseTarget Target Scheduled Scheduled Name Start End (Actual) Start (Actual)End R1 1 Jan. 31 Jan. 1 Jan. 21 Jan. 2015 2015 2015 2015 R2 Up to 2 28Feb. 22 Jan. 11 Feb. weeks before 2015 2015 2015 R1 ends

TABLE 8 Work items following release aware scheduling process WorkEarliest Depends Sched Sched Est Skill Skill Skill item Team ReleaseStart on start end (h) 1 2 3 Priority Project A A, B, C  1 Jan. 2015 11Feb. 2015 290 95 45 150 A A.1 A, B, C  1 Jan. 2015 11 Feb. 2015 290 9545 150 A A.1.1 Team B R2 22 Jan. 2015 11 Feb. 2015 100 100 1 A A.1.2Team C R1  6 Jan. 2015 19 Jan. 2015 40 20 20 2 A A.1.3 Team A R1  1 Jan.2015 14 Jan. 2015 50 50 3 A A.1.4 Team B R1  1 Jan. 2015 21 Jan. 2015100 25 25  50 4 A

Calculated schedule information may also (or alternatively) becommunicated to other processes or applications which may use thescheduling information for downstream purposes.

Preprocessing 902

Preprocessing 902 for the release aware scheduling is illustrated inFIG. 10. The release aware scheduling preprocessing 902 involves thesteps performed in iteration aware scheduling preprocessing 202described above (i.e. steps 402, 404, 406, 408, and 410 of process 202described with reference to FIG. 4). These steps will not be describedagain here.

In addition, preprocessing in the release aware scheduling involves anadditional check at 1002 to determine whether any incompatible releaseassignments/work item dependencies have been defined. This check isperformed to account for the possibility of a dependency relationshipbetween work items conflicting with the temporal relationship of thereleases to which the work items are strictly assigned.

To provide an example of such a conflict consider: two work items A andB are defined; two releases R1 and R2 are defined; work item B isdependent on work item A (i.e. work item B cannot be started until workitem A is completed); work item A is strictly assigned to R2; work itemB is strictly assigned to R1; a relative release start date for R2 isdefined to be dependent on R1. In this situation the causal predecessorrelationship of the work items conflicts with the temporal relationshipof the releases: R2 needs to be completed before R1 (in order for workitem A to be completed before work item B), but R1 needs to be completedbefore R2 (in order to comply with the relative release start date ofR2).

If a conflict of this type is identified an error message is raisedinforming a user of the conflict and the work item dependency is ignoredduring the actual scheduling process.

Scheduling Strictly Assigned Work Items: 904

Following preprocessing at 902, strictly assigned work items arescheduled at 904. This will be described with reference to FIG. 11. Asnoted, a strictly assigned work item is a work item that must becompleted in a particular release.

In order to schedule a strictly assigned work item into a release it isnecessary to consider the scheduling of the strictly assigned work itemitself (which must be scheduled into the assigned release) as well asany causal predecessors to that strictly assigned work item. A causalpredecessor need not be assigned to the same release as its strictlyassigned successor(s), however does need to be scheduled (into anyavailable release) to allow the strictly assigned successor(s) to startand end in the release to which it is strictly assigned.

At 1102 a set of work items to be considered in the scheduling ofstrictly assigned work items phase is generated. This involvesidentifying both strictly assigned work items and, for each strictlyassigned work item identified, any causal predecessor work items to thatstrictly assigned work item.

At 1104, for each work item in the set of work items generated at 1102 alist of possible releases is identified. Each work item is assigned to awork stream. A work stream is assigned an ordered list of releases (theorder typically being a temporal order but not necessarily). Theordering of releases in the stream to which the work item is assigneddefines the list of possible releases for that work item. Differentstreams may relate to any relevant grouping of work, for exampledifferent sub-projects, different product lines or other groupings. Agiven team may work on many different streams, but releases and workitems are assigned to one and only one stream.

For a strictly assigned work item the list of possible releasescomprises, by definition, a single release (i.e. the release to whichthe work item is strictly assigned).

For a causal predecessor work item two cases are distinguished based onwhether the causal predecessor work item is in the same work stream asall of its dependent strictly assigned work item(s) or if it is in adifferent work stream to any of its dependent strictly assigned workitem(s).

If a causal predecessor work item is in a work stream that is differentto all of the work stream(s) its dependent strictly assigned workitem(s) is/are in, the list of possible releases for that work itemcomprises all releases in the causal predecessor work item's workstream.

If a causal predecessor work item's work stream is the same as the workstream of any of its dependent strictly assigned work item(s), the listof possible releases for the work item comprises all releases in thatwork stream except any releases that are dependent on a release whichincludes a strictly assigned work item that is dependent on the causalpredecessor work item.

To illustrate these two cases, consider: a particular stream withreleases [1,2,3,4,5]; a work item A which is strictly assigned torelease [3] (and therefor its set of possible releases is [3]); and awork item B which is not strictly assigned. Under these conditions, theset of possible releases for B is [1,2,3,4,5]. If, however, work item Ais dependent on work item B, the set of possible releases for B becomes[1,2,3] only (releases 4 and 5 being dependent on release 3 to whichwork item A is strictly assigned).

At 1106 release states for all the releases in the sets of potentialreleases identified at 1104 are initialized. If a release has a fixedstart date its state is initialized to be ‘started’. If a release doesnot have a fixed start date its state is initialized to “not-started”.

At 1108 a check is performed to determine whether any of the work itemsidentified at 1102 have not yet been scheduled. If all work itemsidentified at 1102 have been scheduled sub-process 904 ends.

If, at 1108, there are work items in the set of work items identified at1102 that have not been scheduled, the next work item to be scheduled isselected at 1110. This involves processing the prioritized backlog ofwork items identified at 1102. The next work item selected is the firstunscheduled work item in the prioritized backlog that has no unscheduledcausal predecessor work items and for which the first possible releasehas a “started” state. Given the preprocessing described above, and themanner in which the set of releases for a work item are identified at1104, there will initially be at least one valid work hem/release pairto process.

At 1112 an attempt is made to schedule the work item selected at 1110into the first possible release for that work item. In one embodiment,the processing performed in order to schedule the work item into therelease is substantially the same as the work item scheduling process206 (described above with respect to FIG. 5), with a difference being inthe manner in which upper time bounds are used. As described above, whenscheduling a work item without taking releases into account the upperbound is initially set (at 502) to be the planning horizon {umlaut over(T)}. When scheduling a work item taking releases into account analternative upper bound may be initialized for the scheduling process.

If the list of possible releases for the work item being scheduled at1112 has other releases into which the work item can potentially bescheduled the upper time bound for the scheduling process will, if theend date of the first release for the work item is known, be initializedto that end date at 502. This reflects the fact that if the work itemcannot be scheduled into the current release it may be possible toschedule it into another of its potential releases.

Alternatively, if the work item being scheduled at 1112 does not haveany other potential releases into which it can be scheduled (which willalways be the case for a strictly assigned work item) the upper timebound for the scheduling process is initialized at 502 to be theplanning horizon {tilde over (T)}. This reflects the situation that thework item must be scheduled into the release in order to comply with astrict work item assignment, and in this case an attempt to schedule thework item into the release is performed even if it results in the enddate of the release being delayed.

At 1114 a check is performed to see if the scheduling attempt performedat 1112 was successful.

If no schedule could be identified the first release is removed from theset of releases for the work item at 1116. The process returns to 1110to select the next work item/release pair.

At 1118, if the scheduling attempt was successful, an attempt to updaterelease states. Release states can be updated if the work item scheduledat 1118 was the last strictly assigned work item for the release intowhich it was scheduled, and that release has no defined end date. Inthis case the end date for the release is recorded as the end date ofthe iteration into which the work item was scheduled at 1118 (that beingthe date when everything strictly assigned to the release can bedelivered). The end date for the release then serves as an upper boundwhen attempting to schedule other optional work items into that release.Furthermore, if a start time gap has been defined for a dependentrelease (i.e. a release that is dependent on the release whose end datehas been set), the state time for that dependent release is alsoupdated. The start time for the dependent release is calculated byadding the start time gap to the end date of the previous release. Inaddition, the state of the dependent release is set to “started”.

Following 1118 the process returns to 1108 to check whether any otherunscheduled work items exist and need to be scheduled.

Scheduling Unconstrained Release Work Items: 906

Once all strictly assigned work items have been scheduled at 904, all ofthe releases will have start and end dates. Following this, attempts aremade to schedule unconstrained release work items from the backlog. Awork item in the backlog is an unconstrained work item if it is notstrictly assigned and is not a causal predecessor to any strictlyassigned work item. The scheduling of unconstrained release work itemswill be described with reference to FIG. 12.

At 1202 a set of work items to be considered in unconstrained releasework item scheduling phase is generated. This involves identifying workitems that need to be considered in the phase, which include allunscheduled work items.

At 1204 a check is performed to determine whether any of the work itemsidentified at 1202 have not yet been scheduled. If all work items havebeen processed sub-process 906 ends.

If, at 1204, there are work items in the set of work items identified at1202 that have not been scheduled, the next work item is selected at1206. The next work item selected is the highest priority unscheduledwork item without any unscheduled predecessors.

At 1208 possible releases for the work item selected at 1206 areidentified based on an earliest viable start time for the work item. Theearliest viable start time for the work item is determined to be thelatest of the end time(s) of any predecessor work item(s) and anyearliest start date for the work item. A release will be a possiblerelease for the work item if it does not end before the earliest viablestart time for the work item. Conversely, a release wil not be apossible release for a work item if it ends before the earliest viablestart date for the work item.

At 1210 a check is performed to determine if there are possible releasesfor the work item selected at 1206 that have not been checked. If thereare no possible releases, or all possible releases have been checkedwithout a schedule for the work item being identified, an error isgenerated at 1212 to inform a user that the work item (and any successorwork items) cannot be scheduled in the current set of releases. Inaddition, any successor work items to the work item that cannot bescheduled are removed from the set of work items identified at 1202 toavoid unnecessary processing of those work items. The process thenreturns to 1204 to check if there are any other unscheduled work itemsto try and schedule.

If there are possible releases at 1210, the next possible release forthe work item is selected at 1214 according to the order of the releasesin the work stream.

At 1216 an attempt is made to schedule the work item selected at 1206.In one embodiment, the processing performed in order to schedule a workitem is substantially the same as the work item scheduling process 206described above with respect to FIG. 5, with a difference being that theupper bound of the time interval is initialized at 502 to be the enddate of the release selected at 1214.

At 1218 a check is performed to see if the scheduling attempt performedat 1216 was successful. If not, the process returns to 1210 to see ifthere are further releases to try and schedule the work item into.

If the scheduling attempt was successful, the process returns to 1204 tocheck if there are any other unscheduled work items to try and schedule.

4.3 Release Aware Scheduling Clauses

Described herein is a computer implemented scheduling method comprising:accessing project data from computer readable storage media, the projectdata comprising: work item data defining a plurality of work items to bescheduled; release data defining one or more releases into which one ormore of the plurality of work items are to be scheduled; processing,using a computer processor, the project data to schedule strictlyassigned work items by: identifying strictly assigned work items, astrictly assigned work item having a particular release into which thestrictly assigned work item needs to be scheduled; and for each strictlyassigned work item identified: scheduling the strictly assigned workitem into the release specified for that strictly assigned work item.

On scheduling a strictly assigned work item into the specified releasethe method may further comprise: determining if all work items strictlyassigned to the specified release have been scheduled; and responsive todetermining that all work items strictly assigned to the specifiedrelease have been scheduled, calculating an end date for the specifiedrelease.

Responsive to determining that all work items strictly assigned to thespecified release have been scheduled the method may further comprise:identifying a dependent release that is dependent on the specifiedrelease for which the end date was calculated; and calculating a starttime for the dependent release based on the end date calculated for thespecified release.

For each strictly assigned work item identified, processing the projectdata to schedule the strictly assigned work item may further comprise:identifying any causal predecessor work items to the strictly assignedwork item; and scheduling the causal predecessor work items to enablecompletion of the strictly assigned work item in the particular releaseassociated with the strictly assigned work item.

Scheduling a causal predecessor work item may comprise: identifying afirst release into which the causal predecessor work item couldpotentially be scheduled; attempting to schedule the causal predecessorwork item into the first release; responsive to being able to schedulethe causal predecessor work item into the first release, scheduling thecausal predecessor work item into the first release; and responsive tobeing unable to schedule the causal predecessor work item into the firstrelease: identifying a second release into which the causal predecessorwork item could potentially be scheduled; and attempting to schedule thecausal predecessor work item into the second release.

The method may further comprise: processing the project data to identifyunconstrained release work items, an unconstrained release work itembeing a work item that does not need to be scheduled for completion in aparticular release; and for each unconstrained release work itemidentified: attempting to schedule the unconstrained release work iteminto one of the one or more releases.

Scheduling an unconstrained release work item may comprise: identifyinga first release into which the unconstrained release work item couldpotentially be scheduled; attempting to schedule the unconstrainedrelease work item into the first release; responsive to being able toschedule the unconstrained release work item into the first release,scheduling the unconstrained release work item into the first release;and responsive to being unable to schedule the unconstrained releasework item into the first release: identifying a second release intowhich the unconstrained release work item could potentially bescheduled; and attempting to schedule the unconstrained release workitem into the second release.

A release into which an unconstrained release work item can potentiallybe scheduled may be a release which has an end time which is: after anearliest start date of the unconstrained release work item; and afterany end dates of work items on which the unconstrained release work itemis dependent.

Also described herein is a system comprising: one or more processors;one or more non-transitory computer-readable storage media storingsequences of instructions which, when executed by the one or moreprocessors, cause the one or more processors to perform the a method asdescribed in the preceding paragraphs.

5. System Architecture

The processes (and features thereof) described above are implemented byone or more computer processing systems. In the system and hardwaredescriptions below the scheduling functionality will be referred to asbeing provided by a scheduling module. Generally speaking, thescheduling is a set of computer readable instructions and data which,when executed, cause a computer processing system (or systems) toimplement one or more of the features described above.

Various implementations of the scheduling module are possible. Forexample, in one embodiment the scheduling module is implemented as aplugin (also referred to as an add-in, add on, or extension) which isused to extend the capabilities/functionality of a host application. Inone embodiment the host application is Jira, which is commerciallyavailable from Atlassian Pty Ltd., Sydney, Australia. Alternatively, thescheduling module may be implemented as a dedicated, stand-alonescheduling program or application. As a further example, the schedulingmodule may be integrally implemented as part of a broader program orsuite of programs.

In one embodiment the scheduling module may be provided using a clientserver architecture where the scheduling functionality is provided by aserver computer and accessed by users from client computers.

FIG. 13 illustrates a single server client server system 1300. System1300 comprises a server computer 1302. Server computer 1302 hosts aserver application 1304 for providing server-side functionality. Theserver application 1304 comprises one or more application programs,libraries, APIs or other software elements that implement the featuresand functions that are further described herein. The server application1304 includes, inter alia, a scheduling module 1306 which provides thescheduling functionality described above.

Server computer 1302 also stores or has access to data. In this exampledata is stored on and managed by a database 1308, though data could bestored in additional or alternative manners, for example on a local filesystem of the server computer 1302. Database 1308 is provided by adatabase server which may be provided by server 1302, but will moretypically operate on a separate physical computer coupled (directly orindirectly via one or more networks) to server computer 1302.

System 1300 also comprises a user computer 1312. User computer 1312hosts a client application 1314 which provides client-sidefunctionality.

A client application 1314 may be a general web browser application (suchas, for example, Chrome, Safari, Internet Explorer, Opera), in this casethe client application 1314 accesses the server 1304 via an appropriateuniform resource locator (URL) and communicates with the server 1304 viageneral world-wide-web protocols (e.g. http, https, ftp). The webbrowser application is configured to request, render and displayelectronic documents that conform to a markup language such as HTML. XMLor extensions, and may be capable of internally executingbrowser-executable code such as JAVASCRIPT, VBScript, or other forms ofcode. Where the client application 1314 is a web browser, the serverapplication 1304 will be a web server (such as, for example, Apache,IIS, nginx, GWS).

Alternatively, the client application 1314 may be a specific applicationprogrammed to communicate with server 1304 using defined applicationprogramming interface (API) calls. In this case the server 1304 will bea specific application server configured to interact with the clientapplication.

A user computer 1312 may host more than one ITS client 1314 (for examplea general web browser client and a specific application client).Similarly, server computer 1302 may host more than one serverapplication 1314.

The server computer 1302 may serve multiple user computers 1312 (or,more specifically, multiple clients 1314). In FIG. 13 three usercomputers have been depicted (1312A, 1312B, and 1312C), though more orfewer could be used.

The server computer 1302 and client computer 1312 communicate databetween each other either directly or indirectly through one or morecommunications networks 1316. Communications network 1316 may comprise alocal area network (LAN) of an enterprise in one embodiment. In thiscase system 1300 may be implemented as an on-premises solution in whichthe server computer 1302 and user computer 1306 are associated with thesame business enterprise and at least the server computer 1302 is withinan enterprise-controlled facility that is protected from openinternetworks using firewalls or other security systems. In anotherembodiment network 1316 may represent a public internetwork and theserver computer 1302 may be located off-premises with respect to anorganization, such as in a shared data center or cloud computingfacility.

Alternative system implementations/architectures are possible. Forexample, in certain cases a clustered architecture may be used wheremultiple server computing instances (or nodes) are instantiated to meetsystem demand. Conversely, the scheduling functionality described hereinmay be provided by in stand-alone implementation (i.e. a single computerdirectly accessed/used by the end user).

6. Hardware Overview

According to one embodiment, the techniques described herein areimplemented by one or more special-purpose computing devices. Thespecial-purpose computing devices may be hard-wired to perform thetechniques, or may include digital electronic devices such as one ormore application-specific integrated circuits (ASICs) or fieldprogrammable gate arrays (FPGAs) that are persistently programmed toperform the techniques, or may include one or more general purposehardware processors programmed to perform the techniques pursuant toprogram instructions in firmware, memory, other storage, or acombination. Such special-purpose computing devices may also combinecustom hard-wired logic, ASICs, or FPGAs with custom programming toaccomplish the techniques. The special-purpose computing devices may bedesktop computer systems, portable computer systems, handheld devices,networking devices or any other device that incorporates hard-wiredand/or program logic to implement the techniques.

For example, FIG. 14 is a block diagram that illustrates a computersystem 1400 upon which an embodiment of the invention may beimplemented. Server computer 1302 and/or user computer 1312 may becomputer systems such as system 1400.

Computer system 1400 includes a bus 1402 or other communicationmechanism for communicating information, and a hardware processing unit1404 coupled with bus 1402 for processing information. The hardwareprocessing unit 1404 may comprise a single computer processing device(e.g. a general purpose microprocessor, a graphics processing unit, orother computational device), or may comprise a plurality of computerprocessing devices.

Computer system 1400 also includes a main memory 1406, such as a randomaccess memory (RAM) or other dynamic storage device, coupled to bus 1402for storing information and instructions to be executed by processingunit 1404. Main memory 1406 also may be used for storing temporaryvariables or other intermediate information during execution ofinstructions to be executed by processing unit 1404. Such instructions,when stored in non-transitory storage media accessible to processingunit 1404, render computer system 1400 into a special-purpose machinethat is customized to perform the operations specified in theinstructions.

Computer system 1400 further includes a read only memory (ROM) 1408 orother static storage device coupled to bus 1402 for storing staticinformation and instructions for processing unit 1404. A storage device1410, such as a magnetic disk or optical disk, is provided and coupledto bus 1402 for storing information and instructions.

Computer system 1400 may be coupled via bus 1402 to one more outputdevices such as a display 1412 for displaying information to a computeruser. Display 1412 may, for example, be a cathode ray tube (CRT), aliquid crystal display (LCD), a light emitting diode (LED display), or atouch screen display. An input device 1414, including alphanumeric andother keys, may be coupled to bus 1402 for communicating information andcommand selections to processing unit 1404. Another type of user inputdevice is cursor control 1416, such as a mouse, a trackball, or cursordirection keys for communicating direction information and commandselections to processing unit 1404 and for controlling cursor movementon display 1412. This input device typically has two degrees of freedomin two axes, a first axis (e.g., x) and a second axis (e.g., y), thatallows the device to specify positions in a plane. Additional and/oralternative input devices are possible, for example touch screendisplays.

Computer system 1400 may implement the techniques described herein usingcustomized hard-wired logic, one or more ASICs or FPGAs, firmware and/orprogram logic which in combination with the computer system causes orprograms computer system 1400 to be a special-purpose machine. Accordingto one embodiment, the techniques herein are performed by computersystem 1400 in response to processing unit 1404 executing one or moresequences of one or more instructions contained in main memory 1406.Such instructions may be read into main memory 1406 from another storagemedium, such as storage device 1410. Execution of the sequences ofinstructions contained in main memory 1406 causes processing unit 1404to perform the process steps described herein. In alternativeembodiments, hard-wired circuitry may be used in place of or incombination with software instructions.

The term ‘storage media’ as used herein refers to any non-transitorymedia that store data and/or instructions that cause a machine tooperation in a specific fashion. Such storage media may comprisenon-volatile media and/or volatile media. Non-volatile media includes,for example, optical or magnetic disks, such as storage device 1410.Volatile media includes dynamic memory, such as main memory 1406. Commonforms of storage media include, for example, a floppy disk, a flexibledisk, hard disk, solid state drive, magnetic tape, or any other magneticdata storage medium, a CD-ROM, any other optical data storage medium,any physical medium with patterns of holes, a RAM, a PROM, and EPROM, aFLASH-EPROM, NVRAM, any other memory chip or cartridge.

Storage media is distinct from but may be used in conjunction withtransmission media. Transmission media participates in transferringinformation between storage media. For example, transmission mediaincludes coaxial cables, copper wire and fiber optics, including thewires that comprise bus 1402. Transmission media can also take the formof acoustic or light waves, such as those generated during radio-waveand infra-red data communications.

Various forms of media may be involved in carrying one or more sequencesof one or more instructions to processing unit 1404 for execution. Forexample, the instructions may initially be carried on a magnetic disk orsolid state drive of a remote computer. The remote computer can load theinstructions into its dynamic memory and send the instructions over atelephone line using a modem. A modem local to computer system 1400 canreceive the data on the telephone line and use an infra-red transmitterto convert the data to an infra-red signal. An infra-red detector canreceive the data carried in the infra-red signal and appropriatecircuitry can place the data on bus 1402. Bus 1402 carries the data tomain memory 1406, from which processing unit 1404 retrieves and executesthe instructions. The instructions received by main memory 1406 mayoptionally be stored on storage device 1410 either before or afterexecution by processing unit 1404.

Computer system 1400 also includes a communication interface 1418coupled to bus 1402. Communication interface 1418 provides a two-waydata communication coupling to a network link 1420 that is connected toa local network 1422. For example, communication interface 1418 may bean integrated services digital network (ISDN) card, cable modem,satellite modem, or a modem to provide a data communication connectionto a corresponding type of telephone line. As another example,communication interface 1418 may be a local area network (LAN) card toprovide a data communication connection to a compatible LAN. Wirelesslinks may also be implemented. In any such implementation, communicationinterface 1418 sends and receives electrical, electromagnetic or opticalsignals that carry digital data streams representing various types ofinformation.

Network link 1420 typically provides data communication through one ormore networks to other data devices. For example, network link 1420 mayprovide a connection through local network 1422 to a host computer 1424or to data equipment operated by an Internet Service Provider (ISP)1426. ISP 1426 in turn provides data communication services through theworld wide packet data communication network now commonly referred to asthe “Internet” 1428. Local network 1422 and Internet 1428 both useelectrical, electromagnetic or optical signals that carry digital datastreams. The signals through the various networks and the signals onnetwork link 1420 and through communication interface 1418, which carrythe digital data to and from computer system 1400, are example forms oftransmission media.

Computer system 1400 can send messages and receive data, includingprogram code, through the network(s), network link 1420 andcommunication interface 1418. In the Internet example, a server 1430might transmit a requested code for an application program throughInternet 1428, ISP 1426, local network 1422 and communication interface1418.

The received code may be executed by processing unit 1404 as it isreceived, and/or stored in storage device 1410, or other non-volatilestorage for later execution.

A computer system as described herein may be configured in a pluralityof useful arrangements. In one approach, a data processing methodcomprises using a server computer, obtaining from one or morenon-transitory computer-readable data storage media a copy of one ormore sequences of instructions that are stored on the media and whichwhen executed using a particular user computer among a plurality of usercomputers cause the particular user computer to perform, using theparticular user computer alone or in combination with the servercomputer, the techniques that are described herein; and using the servercomputer, downloading the copy of the one or more sequences ofinstructions to any user computer among the plurality of user computers.

In another approach, a computer system comprises a server computercomprising one or more non-transitory computer-readable data storagemedia stored with one or more sequences of instructions which whenexecuted using a particular user computer among a plurality of usercomputers cause the particular user computer to perform: using theparticular user computer, alone or in combination with the servercomputer, the techniques that are described herein; and in the servercomputer, stored downloading instructions which, when executed using theserver computer, cause downloading a plurality of copies of the one ormore sequences of instructions to the plurality of user computers.

A computer system may take a variety of forms. For example, a clientcomputer 1306 may be a desktop computer, a laptop computer, a notebookcomputer, a tablet computer, a smart phone, or other computer.

In the foregoing specification, embodiments of the invention have beendescribed with reference to numerous specific details that may vary fromimplementation to implementation. Thus, the sole and exclusive indicatorof what is the invention, and is intended by the applicants to be theinvention, is the set of claims that issue from this application, in thespecific form in which such claims issue, including any subsequentcorrection. Any definitions expressly set forth herein for termscontained in such claims shall govern the meaning of such terms as usedin the claims. Hence, no limitation, element, property, feature,advantage or attribute that is not expressly recited in a claim shouldlimit the scope of such claim in any way. The specification and drawingsare, accordingly, to be regarded in an illustrative rather than arestrictive sense.

As used herein the terms “include” and “comprise” (and variations ofthose terms, such as “including”, “includes”, “comprising”, “comprises”.“comprised” and the like) are intended to be inclusive and are notintended to exclude further features, components, integers or steps.

A number of flowcharts are provided in order to illustrate processing orfunctional steps. Although these flowcharts define steps in particularorders to explain various features in some cases the steps may be ableto be performed in a different order. Furthermore, in some cases one ormore steps may be combined into a single step, a single step may bedivided into multiple separate steps, and/or the function(s) achieved byone or more of the described/illustrated steps may be achieved by one ormore alternative steps.

It will be understood that the embodiments disclosed and defined in thisspecification extend to all alternative combinations of two or more ofthe individual features mentioned or evident from the text or drawings.All of these different combinations constitute various alternativeaspects of the embodiments.

What is claimed is:
 1. A computer implemented scheduling methodcomprising: accessing project data from computer readable storage mediausing a computer processor, the project data comprising: work item datadefining a plurality of work items to be scheduled; resource datadefining a plurality of resources; team data defining a plurality ofteams, each team being associated with one or more resources and havinga schedule of iterations; performing, by the computer processor,preprocessing to reduce processing time and memory usage of the computerimplemented method; for each work item: processing, using the computerprocessor, the project data to determine one or more team-specificscheduling solutions for the work item, each team specific schedulingsolution for the work item defining a particular team, one or moreiterations of that particular team in which the work item can becompleted, and a number of iteration violations, wherein an iterationviolation occurs when an additional iteration needs to be used tocomplete the work item; wherein the processing takes into account aconstraint that limits each team of the plurality of teams to utilizingthe one or more resources associated with the team as defined by theproject data; identifying from the one or more team-specific schedulingsolutions, using the computer processor, an optimal scheduling solutionfor the work item, the optimal scheduling solution being selected basedat least in part on a least number of iteration violations defined byeach of the one or more team-specific scheduling solutions; andscheduling the work item using the computer processor according to theoptimal scheduling solution identified for the work item.
 2. Thecomputer implemented scheduling method according to claim 1, wherein anoptimal scheduling solution is determined to be a team-specificscheduling solution defining fewest number of iterations of the one ormore team-specific scheduling solutions for the work item.
 3. Thecomputer implemented scheduling method according to claim 2, wherein ifmultiple team-specific scheduling solutions define a same least numberof iterations, the optimal scheduling solution is determined to be theteam-specific scheduling solution which defines the least number ofiterations and an earliest work item completion time.
 4. The computerimplemented scheduling method according to claim 1, wherein processingthe project data to determine one or more team-specific schedulingsolutions for a given work item comprises, for each team available towork on the given work item, processing the project data to try anddetermine a team-specific scheduling solution for the given work itemfor that team.
 5. The computer implemented scheduling method accordingto claim 4, wherein each work item comprises one or more work itemactivities, and wherein processing the project data to determine ateam-specific scheduling solution in respect of a given work item and agiven team comprises: processing the project data to determine a finalassignment for each activity of the given work item, the team specificscheduling solution for the given work item comprising the finalassignments for all activities of the given work item, and wherein afinal assignment in respect of a particular activity of the given workitem defines a sub-team of the given team and one or more iterations inwhich the sub-team can complete the particular activity of the givenwork item.
 6. The computer implemented scheduling method according toclaim 5, wherein determining a final assignment for a given activity ofa given work item for a given team comprises: generating a queue ofsolution candidates, each solution candidate defining a sub team of thegiven team and one or more iterations; determining a heuristic solutionquality for each solution candidate in the queue of solution candidates;selecting a current solution candidate from the queue of solutioncandidates, the current solution candidate being the solution candidatewith a best heuristic solution quality; determining whether anassignment for the given activity and current solution candidate exists;and responsive to determining that an assignment for the given activityand current solution candidate exists, determining that assignment to bethe final assignment for the given activity; or responsive todetermining that no assignment for the given activity and currentsolution candidate exists, attempting to determine an assignment for thegiven activity and a different or updated solution candidate.
 7. Thecomputer implemented scheduling method according to claim 6, wherein theheuristic solution quality for a given solution candidate is based onthe number of iterations defined by the given solution candidate and anend time of a latest iteration defined by the solution candidate.
 8. Thecomputer implemented scheduling method according to claim 1, furthercomprising processing the project data to identify and remove fromfurther processing work items that cannot be scheduled.
 9. The computerimplemented scheduling method according to claim 8, wherein the projectdata further comprises dependency data defining one or more dependencyrelationships between work items, and wherein identifying and removingwork items that cannot be scheduled comprises processing the dependencydata to identify and remove work items with cyclic dependencies.
 10. Thecomputer implemented scheduling method according to claim 9, whereinidentifying and removing work items that cannot be scheduled furthercomprises identifying and removing work items which are dependent on awork item with a cyclic dependency.
 11. The computer implementedscheduling method according to claim 8, wherein the project data furthercomprises: work item skill data defining, for a given work item, one ormore skills required in order to complete the given work item, andresource skill data further defines, for a given resource, one or moreskills held by the given resource; and wherein identifying and removingwork items that cannot be scheduled comprises processing the projectdata to identify and remove any work items that require at least oneskill that is not held by any resource.
 12. The computer implementedscheduling method according to claim 1, further comprising processingthe project data to identify and remove from further processingresources that cannot contribute to completion of any work item.
 13. Thecomputer implemented scheduling method according to claim 12, whereinthe project data further comprises: work item skill data defining, for agiven work item, one or more skills required in order to complete thegiven work item, and resource skill data further defines, for a givenresource, one or more skills held by the given resource; and whereinidentifying and removing resources that cannot contribute to thecompletion of any work item comprises processing the project data toidentify and remove any resource that does not hold one or more skillsrequired by any work item.
 14. A system comprising: one or moreprocessors; one or more non-transitory computer-readable storage mediastoring sequences of instructions which, when executed by the one ormore processors, cause the one or more processors to: access projectdata from the one or more non-transitory computer-readable storage mediausing the one or more processors, the project data comprising: work itemdata defining a plurality of work items to be scheduled; resource datadefining a plurality of resources; team data defining a plurality ofteams, each team being associated with one or more resources and havinga schedule of iterations; performing preprocessing to reduce processingtime and memory usage of the computer implemented method; for each workitem: process the project data using the one or more processors todetermine one or more team-specific scheduling solutions for the workitem, each team specific scheduling solution for the work item defininga particular team, one or more iterations of that particular team inwhich the work item can be completed, and a number of iterationviolations, wherein an iteration violation occurs when an additionaliteration needs to be used to complete the work item; wherein theprocessing takes into account a constraint that limits each team of theplurality of teams to utilizing the one or more resources associatedwith the team as defined by the project data; identify from the one ormore team-specific scheduling solutions using the one or more processorsan optimal scheduling solution for the work item, the optimal schedulingsolution being selected based at least in part on a least number ofiteration violations defined by each of the one or more team-specificscheduling solutions; and scheduling the work item using the one or moreprocessors according to the optimal scheduling solution identified forthe work item.
 15. The system according to claim 14, wherein an optimalscheduling solution is determined to be a team-specific schedulingsolution defining a fewest number of iterations of the one or moreteam-specific scheduling solutions for the work item.
 16. The systemaccording to claim 15, wherein if multiple team-specific schedulingsolutions define a same least number of iterations, the optimalscheduling solution is determined to be the team-specific schedulingsolution which defines the least number of iterations and an earliestwork item completion time.
 17. The system according to claim 14, whereinprocessing the project data to determine one or more team-specificscheduling solutions for a given work item comprises: for each teamavailable to work on the given work item, processing the project data totry and determine a team-specific scheduling solution for the given workitem for that team.
 18. The system according to claim 17, wherein eachwork item comprises one or more work item activities, and whereinprocessing the project data to determine a team-specific schedulingsolution in respect of a given work item and a given team comprises:processing the project data to determine a final assignment for eachactivity of the given work item, the team specific scheduling solutionfor the given work item comprising the final assignments for allactivities of the given work item, and wherein a final assignment inrespect of a particular activity of the given work item defines asub-team of the given team and one or more iterations in which thesub-team can complete the particular activity of the given work item.19. The system according to claim 18, wherein determining a finalassignment for a given activity of a given work item for a given teamcomprises: generating a queue of solution candidates, each solutioncandidate defining a sub team of the given team and one or moreiterations; determining a heuristic solution quality for each solutioncandidate in the queue of solution candidates; selecting a currentsolution candidate from the queue of solution candidates, the currentsolution candidate being the solution candidate with a best heuristicsolution quality; determining whether an assignment for the givenactivity and current solution candidate exists; and responsive todetermining that an assignment for the given activity and currentsolution candidate exists, determining that assignment to be the finalassignment for the given activity; or responsive to determining that noassignment for the given activity and current solution candidate exists,attempting to determine an assignment for the given activity and adifferent or updated solution candidate.
 20. The system according toclaim 19, wherein the heuristic solution quality for a given solutioncandidate is based on the number of iterations defined by the givensolution candidate and an end time of a latest iteration defined by thesolution candidate.
 21. The system according to claim 14, wherein thesequences of instructions, when executed, further cause the one or moreprocessors to process the project data to identify and remove fromfurther processing work items that cannot be scheduled.
 22. The systemaccording to claim 21, wherein the project data further comprisesdependency data defining one or more dependency relationships betweenwork items, and wherein identifying and removing work items that cannotbe scheduled comprises processing the dependency data to identify andremove work items with cyclic dependencies.
 23. The system according toclaim 22, wherein identifying and removing work items that cannot bescheduled further comprises identifying and removing work items whichare dependent on a work item with a cyclic dependency.
 24. The systemaccording to claim 21, wherein the project data further comprises: workitem skill data defining, for a given work item, one or more skillsrequired in order to complete the given work item, and resource skilldata further defines, for a given resource, one or more skills held bythe given resource; and wherein identifying and removing work items thatcannot be scheduled comprises processing the project data to identifyand remove any work items that require at least one skill that is notheld by any resource.
 25. The system according to claim 14, wherein thesequences of instructions, when executed, further cause the one or moreprocessors to process the project data to identify and remove fromfurther processing resources that cannot contribute to completion of anywork item.
 26. The system according to claim 25, wherein the projectdata further comprises: work item skill data defining, for a given workitem, one or more skills required in order to complete the given workitem, and resource skill data further defines, for a given resource, oneor more skills held by the given resource; and wherein identifying andremoving resources that cannot contribute to the completion of any workitem comprises processing the project data to identify and remove anyresource that does not hold one or more skills required by any workitem.